MTD ITSA is straightforward in principle — keep digital records, file quarterly summaries. In practice, the first year catches a surprising number of sole traders out. These are the five most common mistakes, and exactly how to avoid each one.
Use the MTD Readiness Checker to confirm you've got the basics covered — software connected, records digital, and deadlines set.
The first quarterly filing deadline catches many sole traders off guard. Under Self Assessment, you had one deadline to remember: 31 January. Under MTD, there are now four quarterly deadlines per year plus an end-of-period statement and final declaration.
The Q1 submission (covering 6 April – 5 July 2026) is due by 7 August 2026. That's a much shorter window than most sole traders are used to — the period ends and you have just 33 days to file.
Under HMRC's points-based penalty system, each late submission earns a penalty point. Accumulate four points and you receive an automatic £200 fine. That's potentially £200 in fines before you even notice the pattern.
Set calendar reminders for each deadline now: 7 Aug, 7 Nov, 7 Feb, 7 May. Better yet, use software like Neatly that alerts you when a filing window is open and lets you submit in minutes once your bank transactions are categorised.
MTD ITSA requires digital records — but many sole traders interpret this loosely. Scanning receipts as PDFs and dropping them in a folder doesn't constitute digital record-keeping under MTD. You need records that are stored in a format your MTD-compatible software can read, categorise, and submit.
The problem compounds when sole traders start the tax year on paper and try to migrate to digital mid-year. HMRC expects digital records from the start of your MTD obligation. Late conversion means manually re-entering months of transactions — a painful and error-prone process.
HMRC requires you to keep records for at least 5 years after the relevant 31 January filing deadline. If you're ever investigated, paper records that were "also" kept won't substitute for the required digital records.
Connect your business bank account to MTD software before the new tax year starts. With Neatly, your transactions import automatically from your bank — no manual entry required. Every transaction is recorded digitally from the moment it hits your account.
Not all bookkeeping software is MTD-compatible. Some popular accounting tools have MTD features locked behind premium tiers. Others require separate "bridging software" to push data to HMRC's API. And some older tools simply don't support MTD ITSA at all — they may have MTD VAT functionality but not the newer Income Tax submission pipeline.
The problem is that you often don't discover the incompatibility until you try to file. At that point, you're either scrambling to switch software and migrate your data, or paying for a last-minute bridging solution.
Bridging software is technically permitted by HMRC but is widely considered a workaround, not a long-term solution. It introduces an additional step between your records and HMRC — and more steps mean more opportunities for error.
Verify before you commit that your software can submit MTD ITSA quarterly updates directly to HMRC — not just MTD VAT returns. Ask specifically: "Does this submit income tax quarterly updates under MTD ITSA?" Neatly is built for MTD ITSA from the ground up, with direct HMRC API connectivity.
Under Self Assessment, mixing personal and business bank accounts was common — many sole traders used one account for everything and sorted it out at year end. Under MTD, this approach creates serious problems.
MTD requires quarterly submissions. If your business transactions are interleaved with personal spending, every reconciliation becomes a manual exercise in identifying and excluding personal items. Do that four times per year and you've created significantly more work than a single annual sort.
Worse: HMRC's systems receive your categorised summaries. If personal expenses accidentally make it through as business expenses — which is far more likely when accounts are mixed — you're looking at potential compliance queries and underpaid tax.
Open a dedicated business bank account if you don't already have one. Many UK challenger banks offer free business current accounts with no monthly fees. Connect that account to Neatly, and all your transactions are automatically classified as business by default — no filtering required.
MTD ITSA requires you to sign up with HMRC before your software can submit on your behalf. This isn't automatic. You need to authorise the connection between HMRC and your MTD software — and that process can take several days if there are any issues with your HMRC account.
Sole traders who leave registration until the week before their first deadline sometimes encounter issues: identity verification delays, agent authorisation problems, or technical errors with HMRC's online services. None of these are unusual — but they take time to resolve, time you don't have if you've left it to the last week of July.
Additionally, if you use an accountant to manage your MTD filings, they need to be authorised through HMRC's Agent Services Account — a separate process that requires your accountant to have already set up their agent account.
Sign up for MTD ITSA now, not in late July. The process takes about 15 minutes when everything works smoothly — but allow 2 weeks in case HMRC's systems require manual intervention. Neatly guides you through the HMRC authorisation process step by step.
All five mistakes share the same root cause: treating MTD as a once-a-year task rather than an ongoing process. The sole traders who handle MTD with minimal stress are the ones who set it up properly in April and let their software handle the quarterly routine automatically.
MTD is not designed to be a burden for well-organised businesses. It is designed to penalise disorganisation. The fix is not to work harder — it's to connect your bank account to software that makes the digital record-keeping invisible.
Penalty points don't reset on 6 April. Points accumulated in 2026/27 carry into 2027/28. A rocky first MTD year — where you miss two or three quarterly deadlines — can start your second year already partway to a £200 fine.
Neatly connects to your bank, categorises transactions automatically, and keeps you on track for every quarterly deadline. Built specifically for UK sole traders under MTD.
Start free → Check my MTD statusEverything you need to do before your first quarterly deadline. 15 steps, HMRC-aligned, updated for April 2026.
🔒 No spam. Just MTD compliance tips. Unsubscribe anytime.
15 steps every UK sole trader needs before April 2026. Takes 5 minutes to complete.
No spam. Unsubscribe any time.