The number that changed how I think about software came from one household. A couple I act for jointly own three UK properties and a Spanish apartment, and one of them runs a self-employed consultancy.
Under MTD they do not file five times a year. They file twenty-two, because each owner reports each income type separately every quarter, then once more at year end.
Multiply that across the few hundred landlords and sole traders on my books and the question stops being how to file. It becomes which platform can carry the volume without a second subscription, a spreadsheet workaround, or a missed deadline.
What I had not settled, and what most practices still have not, is what to run it on. That one choice quietly sets everything after it: the hours each client costs you, whether your team survives five filing seasons a year instead of one, and whether the fee you quote today still works three years from now.
I run a property tax practice with thousands of clients and built the platform we use to manage them, so what follows is the evaluation I wish someone had handed me before any of it was locked in.
For the regime itself, our main MTD ITSA guide carries the detail (internal link to be confirmed).
Why "MTD-Ready" Software Does Not Mean Ready for Your Practice
Every vendor claims to be MTD-ready, so the label tells you nothing. The real question is narrower. Can this platform carry your whole client book through four quarters and a year-end without manual workarounds?
Being able to submit one quarterly update to HMRC is the entry ticket. It is not what separates a platform that runs your practice from one that files a single return.
Three capabilities decide that. Most products manage one. Very few manage all three.
Every income type in one client record: UK property, foreign property, and self-employment, without forcing you onto a second platform for mixed-income clients. A landlord who also runs a sole trade, or a sole trader who also lets property, falls into a gap that many platforms cannot bridge.
Property accounting handled natively: Automatic joint ownership splits at any ratio, Section 24 finance cost categorisation enforced at the point of entry, per-property profitability, letting agent statement imports, and foreign property with per-country tracking and currency conversion. These are the core mechanics of property tax under MTD, not optional extras.
Practice-scale operation: A multi-client dashboard showing every client, every quarter, every deadline. Bulk information requests. Client approval workflows. Review and sign-off sequences. HMRC filing from the dashboard. Status across the entire client base, not one client at a time.
You Are Choosing a Workflow Tool, Not a Filing Button MTD ITSA is not a calculation change. It is a workflow change. The underlying tax calculation is identical: the same allowable expenses, the same Section 24 restriction, the same capital allowances rules. What changes is the record-keeping and the reporting rhythm. A practice that used to touch each client's file once a year will now touch it at least five times. Every workflow inefficiency in the annual model is multiplied by five under MTD, which is why the platform you choose matters more than the calculation it performs. |
The Software Test: Can It File UK Property, Foreign Property and Self-Employment on One Client Record?
This is the first test, and it is where most selections go wrong. The practice evaluates the platform against its simplest clients, confirms it works, and rolls it out. Six weeks later it meets the client with a Spanish apartment, the couple who own 70:30, or the sole trader who also lets a flat, and the platform cannot file them in one place.
HMRC recognition is granted per income type. UK property, foreign property, and self-employment are separate recognitions, and most software does not hold all three. The practical consequences:
General-purpose accounting software | Landlord-specific software |
|---|---|
General-purpose accounting software (Xero, QuickBooks, Sage) typically handles self-employment well, and some now cover UK property. But at the time of writing, none of these platforms support foreign property filing under MTD. Property features like joint ownership splits and Section 24 categorisation are either absent or require manual workarounds. | Landlord-specific software typically handles UK property well, sometimes covers foreign property, but usually does not handle self-employment at all. A landlord who also runs a trade needs a second platform. |
That is the two-platform problem. When one platform cannot cover all of a client's income types, you run two products for the same client. Two subscriptions, two sets of records, two filing workflows, and a reconciliation exercise at year-end. Sustainable for one or two clients. Not sustainable across a practice.
Before you shortlist anything, audit your client base for multi-source clients. If a meaningful proportion of your landlord clients also have self-employment income, or any have foreign property, you need software that covers all three types, or a clear plan for running two platforms per client and absorbing the cost.
Capability | Generic accounting | Landlord-specific | All-in-one property + SE |
|---|---|---|---|
Self-employment | ✓ | ✗ | ✓ |
UK property | △ generic ledger | ✓ property ledger | ✓ property ledger |
Foreign property | ✗ | △ some | ✓ |
Joint ownership splits | ✗ | △ limited | ✓ |
Section 24 at point of entry | ✗ | △ limited | ✓ |
Letting agent statement import | ✗ | △ some | ✓ |
Accountant dashboard | △ basic | ✗ | ✓ |
The Software Test: Can You See Every Client and Every Deadline in One View?
A platform that shows you one client's position is a client tool. The one you need shows every client's position across every quarter. That is the difference between a bookkeeping product and a platform built to run a practice.
Here is what a practice-grade MTD dashboard should give you:
Status across your client base: Every MTD client visible at once, with a status for each: Not Started, Information Requested, In Progress, Awaiting Approval, Filed. In one view you should see which clients are on track and which are blocking the cycle. An “Overdue” flag overlays any status where the deadline has passed.
Deadline tracking and risk flags: What is due this week, this month, and what is overdue, colour-coded so you do not have to read every row. The dashboard should sort and filter by deadline, by status, by team member, and by client type.
Bulk information requests: After each quarter-end you need to confirm every in-scope client's data is complete. Doing that manually for 200 clients is 200 emails. From the dashboard it is one click, templated, personalised with the client's name and the quarter reference, and tracked so you can see who has responded and who has not.
Client approval workflow: Every quarterly update should be approved by the client before filing, and the approval should be structured, fast, and auditable. An email asking “please confirm this is OK” is slow and leaves no record. A structured in-software approval with a secure link, a one-click confirm button, and a timestamped audit trail resolves in hours rather than days.
Direct HMRC submission: File quarterly updates and Final Declarations directly from the dashboard. No export, no separate portal, no manual step between review and submission.
If your shortlisted software does not offer practice-level visibility across the entire client base, you are managing the regime blind.
That holds up in the first quarter, when volumes are low and goodwill is high. It does not hold up in the third, when the novelty has worn off and the deadlines keep coming.
The Software Test: Does It Run the Quarterly Cycle, or Just File the Return?
Filing is the easy part. The work that breaks practices is everything around it: chasing the data, reviewing it, getting the client to approve it, then doing that for the whole book, four times a year. The platform you choose either runs that cycle or leaves you to manage it by hand. Test it against the six stages below.
Stage | When | Who | What happens |
|---|---|---|---|
Data capture | Ongoing through the quarter | Client + automation | Bank feeds, letting agent imports, and receipt scanning populate the software continuously |
Data cut-off and chase | Week before quarter-end | Firm (automated) | Client receives checklist, outstanding items flagged, last-minute reminders sent |
Review and categorisation | Week after quarter-end
|
Bookkeeper | Transactions reviewed, exceptions queried, uncategorised items resolved, Section 24 costs segregated |
Senior sign-off | Days 10 to 14 after quarter-end | Manager or partner | Draft submission reviewed, signed off or queried |
Client approval | Days 14 to 28 after quarter-end |
Client | Client receives draft summary, confirms or queries, authorises submission |
File and confirm | Before filing deadline |
Firm | Quarterly update filed via MTD API, filing receipt captured, client confirmation sent |
Three Rules That Keep You Ahead of the Filing Deadline
Work starts before the quarter ends, not after
If your team's first look at a quarter's data is on 6 July, the 7 August deadline is already under pressure. The data cut-off chase should start in the last week of the quarter. Clients appreciate fewer last-minute asks, and firm-side capacity is smoothed across a longer window.
The deadline is internal, not external
Using HMRC's 7th-of-the-month deadline as your internal deadline is a recipe for accumulating penalty points. Set the firm's internal deadline five to seven days earlier and use the buffer for the inevitable client who goes quiet for a fortnight. The firm that files on the 2nd or 3rd has capacity to spare. The firm that files on the 7th has none.
Client approval is a step, not an afterthought
Every quarterly update should be reviewed by the client before filing, which protects the practice as much as the client. A structured approval workflow, with a secure link and a timestamped record, is the fastest way to close the cycle.
The Software Test: Can It File in Both Main and Supporting Agent Roles?
MTD lets a client have two agents at once, with different levels of authority, so your platform needs to file in whichever role you hold.
The Main agent has full access: quarterly updates, the Final Declaration, the client's complete income picture, and authorisation management. The Supporting agent can file quarterly updates and contact HMRC about the client's returns, but cannot access the Final Declaration, the client's non-business income, or the in-year tax calculations.
Late-submission penalty notices also go to the Main agent, not the Supporting agent, which matters when your firm files the quarterly updates while another firm holds the Main agent role.
Opportunity for a Specialist Accounting Firm
A property bookkeeping practice can offer a Supporting agent service, handling the quarterly update mechanics for other firms' clients, while the primary accountant retains the Main agent role for the year-end and advisory work. The Supporting agent handles the volume; the Main agent handles the complexity.
The economics work at scale. A specialist property firm handling 100 quarterly-update-only clients at £600 per year each generates £60,000 of annual revenue from a highly standardised, automatable workflow.
The margin per client is lower than a full-service engagement, but the time per client is far less. At volume, this is one of the most profitable service lines in an MTD practice.
If you are a generalist practice that does not want to build a quarterly property workflow, the Supporting agent model gives you a referral route. If you are a specialist property firm, it gives you a new revenue stream. Either way, check the platform can file in the role you intend to hold.
How Should Accountants Price the Work So They Are Not Locked Into a Loss
Software belongs in a pricing discussion because it is the biggest lever on what each client costs you to serve.
Get the platform right and the per-client time falls, which is what lets the price work. Get it wrong and you carry it for years, because of what I call the lock-in: once a client is onboarded at a price and the quarterly rhythm has settled, raising the fee later is difficult. Over-price instead and clients leave for less specialist firms willing to quote £500 for work that should cost £1,500.
Flat pricing fails under MTD. Two clients who both own two properties can have wildly different Final Declaration complexity. One is a basic-rate taxpayer with property income only. The other has PAYE employment, dividends, pension contributions, Gift Aid, and a carried-forward capital loss.
The quarterly updates are identical, but the Final Declaration is four times the work. Pricing them the same is either a windfall on one or a loss on the other.
What Drives the Cost of Serving an MTD Client
Factor | Effect on price |
|---|---|
Number of qualifying businesses (each needs quarterly submissions) | + per business |
Number of properties (transaction volume) | + per property |
Joint ownership (multiple owner-level submissions from same data) | + significant |
Foreign property (separate quarterly obligation, currency conversion) | + significant |
Letting agent managed vs self-managed | Agent = lower; self-managed = higher |
Client's digital capability (firm-led vs client self-entry) | + if firm-led bookkeeping |
Non-resident landlord (time zones, NRLS, agent liaison) | + significant |
PAYE, dividends, savings, pensions (additional Final Declaration sources) | + moderate per source |
Capital gains (disposals, 60-day CGT reconciliation) | + significant |
Double tax relief for foreign property | + significant per country |
Loss relief claims or carry-forwards | + moderate to significant |
Main vs Supporting agent role | Supporting = lower base fee |
When you select the relevant variables for a specific client, the price emerges from the combination, not from a guess, not from a tier, and not from whatever the partner remembered charging last year.
Two clients with the same number of properties but very different Final Declaration complexity will receive different prices, as they should.
Do not just multiply your Self Assessment fee by four A firm currently charging £300 for a client's annual Self Assessment should not charge £300 for MTD with “a bit more” on top. The work is three to five times the volume: four quarterly reviews, quarterly client chasing, software setup, quarterly internal sign-off, and annualised advisory. Re-price from scratch using the variable framework, based on the time the service now takes plus your target margin. |
Three Ways to Bill, and When Each Protects Your Margin
Fixed annual fee: A single all-in annual fee covering all quarterly updates and the Final Declaration, billed monthly by direct debit. Predictable revenue, simple to explain, easy to automate. Best for straightforward clients where scope is unlikely to change.
Per-submission pricing: A price per quarterly update plus a separate price for the Final Declaration, billed as each filing is completed. Fees match the work precisely, and if the client leaves mid-year you have been paid for the work done. Best for Supporting agent engagements.
Monthly subscription: A flat monthly fee covering everything, with explicitly priced add-ons for out-of-scope work. Smooth revenue, encompasses all MTD deliverables, and permits continuous advisory without the “another invoice” friction. Best for complex clients and practices positioning as ongoing advisers.
Your Service Price Holds or Fails on What the Quarterly Work Costs You to Deliver
Under Self Assessment your capacity peak is January. Under MTD you have five: August, November, February, May, and January, and the August peak is the worst because it lands in the school holidays and annual leave. Whether your team absorbs that depends almost entirely on how much the software automates.
Run this with your existing client base. Pick your top 20 Self Assessment clients by fee and assume each becomes MTD-in-scope.
For each, estimate the hours the four quarterly updates will take, the touchpoints the team will need, and the total annualised fee required to keep your current margin.
If the answer is not obviously commercial, your workflow has to change before you price. If you price first, you are locked into an uncommercial engagement for years.
The capacity plan has three levers, and the first one is a direct software question:
Automation: Bank feeds, automated categorisation, letting agent statement imports, and bulk information requests reduce the human time per client per quarter. Every manual step the software removes is time recovered across every client, every quarter.
Team structure: The quarterly review cycle works best with a clear three-tier structure: bookkeeper prepares, senior reviews, partner signs off. Each tier handles the work appropriate to their cost rate. A practice where the partner reviews every transaction is burning capacity at the most expensive level.
Outsourcing or Supporting agent referral: For the quarterly mechanics specifically, outsourcing to a specialist team or referring the quarterly work to a Supporting agent frees internal capacity for the advisory and year-end work where margins are highest.
Why your Self Assessment Engagement Letter No Longer Covers the Work
A Self Assessment engagement letter that says “we will file your return” is inadequate for a service that includes five distinct filings, quarterly client data obligations, and ongoing digital record-keeping.
The MTD engagement letter needs to cover:
Quarterly scope: Explicitly what the practice does each quarter: data review, categorisation, Section 24 segregation, quarterly update preparation, client approval, HMRC submission.
Client obligations: What the client must provide, and by when, after each quarter-end. If the client consistently provides information late, what follows? Not a threat, but a practical statement that late data may mean the filing deadline is missed, with the associated penalty risk sitting with the client.
Final Declaration scope: What additional work is included at year-end: other income sources, capital gains, relief claims, and the personal approval requirement. If the practice charges separately for the Final Declaration, this is where the fee is stated.
Out-of-scope triggers: What causes a re-price: additional properties, new businesses, a change from self-entry to firm-managed bookkeeping, mid-year ownership changes, foreign property added. Listing these upfront prevents disputes later.
Agent role: Whether the practice acts as Main agent or Supporting agent, and what that means for the client in practical terms.
For joint-owner landlords, issue separate engagement letters for each co-owner. Under MTD, each co-owner has separate obligations, separate deadlines, and separate penalty exposure. A single letter covering both creates ambiguity about scope, liability, and fee allocation.
For non-resident landlords, the letter must also cover the NRLS interaction, agent statement collection responsibilities, approval timelines adjusted for time zones, and whether the practice handles local country tax returns.
Six Software-Selection Mistakes That Cost You Every Quarter
A few selection mistakes show up again and again. Each one costs time every quarter, for every client.
Choosing software on what your existing platform already does, rather than on whether it handles property natively, foreign property, and joint ownership without manual workarounds.
Evaluating the software against your simplest client instead of your most complex one. The platform that handles the couple with five properties at mixed ratios, a foreign apartment, and self-employment income is the one that scales.
Treating the multi-client dashboard as optional. It is the feature that decides whether you manage the regime at practice level or one client at a time.
Leaving the workflow design until after the first quarter, when the team is already scrambling.
Assuming all MTD software is equivalent. HMRC recognition is granted per income type, and property-specific features are either built in or they are not.
Pricing MTD as Self Assessment with a small uplift, when the work is three to five times the volume.
Ten Questions to Ask While Evaluating an MTD Software
Rather than comparing products feature by feature, put these ten questions to any MTD platform on your shortlist.
The answers tell you whether it can run your practice or just file individual returns.
# | Question | Why it matters |
|---|---|---|
1 | Does it cover all three income types (UK property, foreign property, self-employment)? | A client with mixed income triggers a second platform if it does not |
2 | Does it handle joint ownership with per-property splits at any ratio? | Manual split calculations every quarter do not scale |
3 | Does it enforce Section 24 categorisation at point of entry? | Retrofitting the categorisation at quarter-end adds time and error risk |
4 | Does it import letting agent statements (PDF or CSV)? | Agent-managed properties are the majority of property portfolios |
5 | Does it support both quarterly updates and the Final Declaration? | Software that only handles quarters leaves you without a year-end filing route |
6 | Does it have a multi-client dashboard with status and deadline tracking? | Without it, you are managing the regime one client at a time |
7 | Does it support bulk information requests and client approval workflows? | Manual chasing for 200 clients per quarter is not sustainable |
8 | Does it handle foreign property with per-country tracking and currency conversion? | The software gap for foreign property is the most acute in the market |
9 | Can you file directly to HMRC from the platform? | An export-and-upload step adds time and breaks the audit trail |
10 | Is it built by people who actually deliver MTD engagements? | Software designed by accountants solves different problems than software designed by developers |
If the answer to any of these is no, you have found a gap that will cost you time, money, or both across the quarterly cycle.
How We Built RentalBux Against this Checklist
I want to be transparent about this section. RentalBux is the platform I built for my own practice, and I am naturally going to think it is the right answer. But I am not writing about it to sell you software.
When it comes to RentalBux, every one of the ten questions above has a yes behind it for a reason, and the reasons are the same problems I have described throughout this guide. Understanding them will help you evaluate any platform, including ours.
RentalBux was built inside a UK accountancy practice, not by a technology company guessing what accountants need. Every feature exists because our team needed it for real clients.
The accountant dashboard exists because we needed to see 500 clients in one view. The joint ownership engine exists because 60% of our clients own property jointly. Foreign property support exists because we act for landlords across more than 50 countries. Section 24 categorisation is enforced at the point of entry because we got tired of fixing it at quarter-end.
RentalBux holds HMRC recognition across all three MTD ITSA income types: UK property, foreign property, and self-employment.
At the time of writing, it also holds approval for the Final Declaration and has received recognition for major categories of tax return items beyond MTD-mandated income, including PAYE, interest, dividends, and student loans. The remaining categories are in development and expected to be completed by autumn 2026, well before the first tax year-end.
RentalBux Capabilities That Map to the Checklist
Capability | What it does for the practice |
|---|---|
HMRC-recognised submissions | Quarterly updates and Final Declaration filed directly to HMRC from the dashboard |
UK property, foreign property, self-employment | All three income types on one client record, filed to the correct HMRC API endpoints |
Property-level P&L | Profitability by property, by portfolio, and by owner |
Joint ownership engine | Split percentages held at property level, applied automatically on submission. Form 17 tracked with audit trail |
Section 24 handling | Finance costs routed to the residential finance category at point of entry. Basic-rate credit calculated at Final Declaration |
Bank feeds | Live feeds from UK banks, with split-tagging at transaction level |
Letting agent statement import | Import from PDF or CSV. Gross rent, management fees, repairs, and net payments extracted and categorised automatically |
Foreign property | Per-country and per-property tracking, multi-currency recording, property ID support for HMRC's identification requirement |
Accountant dashboard | Every client, every quarter, every deadline. Traffic-light status, bulk information requests, client approval tracking |
How RentalBux and FigsFlow Cover the Full Cycle
RentalBux handles the ledger: digital records, quarterly submissions, the Final Declaration, and ongoing practice-level visibility. FigsFlow, our practice management platform, handles the pre-engagement: pricing, proposals, engagement letters, AML, and automated payment setup.
The handover point is the moment the engagement is signed, when the client record flows from FigsFlow into RentalBux automatically. The bookkeeper starts with a populated client record, not a blank screen.
The combination means the full cycle, from pricing a new client through to filing their fourth quarterly update, runs on two integrated platforms without a spreadsheet, a Word template, or a manual data entry step in between.
If you want to see how RentalBux and FigsFlow handle the full practice workflow, from pricing and proposals through quarterly updates to the Final Declaration, you can start a free trial at app.rentalbux.com/register or book a practice walkthrough at rentalbux.com/book-demo. |
Before You Choose Anything, Audit Your Client Base
If you take one thing from this guide, make it the client-base audit. Count the income types, the joint owners, the foreign properties, and the non-residents in your book.
That audit tells you what your software actually needs to do, and it is the input to both your workflow design and your pricing. Most platforms that looked adequate before the audit look inadequate after it.
Then run a dry quarter with your ten most complex clients before you roll out to the full base. The mistakes you catch in a dry run are the ones that would otherwise cost you money in a live quarter.
MTD is a workflow redesign, not a compliance add-on. The practices that treat it as such, and choose software to match, will build something genuinely valuable out of the change.
