For accounting firms
Busy season tax prep support
Busy season support gives UK practices extra hands around Self Assessment and Corporation Tax deadlines: source documents organised, trial balances tied out and draft SA100 or CT600 input completed in your practice's own software, ready for your ASA-holding adviser to review and lodge. Finbryn never files anything with HMRC.
Engagement tracker
Illustrative client · August 2026
GBP
- Client file access set up under your firm's nameDone
- Monthly books prepared to your review standardDone
- Review notes cleared and loggedIn progress
- Reports sent to your partner for sign-offNext
- Year-end workpapers staged for your preparerNext
Illustrative. An example of the document, not a client's figures.
The deadline every UK practice feels
Self Assessment's online deadline falls on 31 January (11:59pm on 31 January 2027 for the 2025-26 tax year), with paper returns due by 31 October the year before. A Company Tax Return is due 12 months after the accounting period ends, though Corporation Tax itself is payable 9 months and 1 day after that period ends, ahead of the filing deadline. Layering those windows across a client book is what turns January into the busiest month on the calendar.
What our team prepares
Work starts with the source documents a client has sent over: bank statements, dividend vouchers, P60s, prior-year returns and the bookkeeping behind them. We tie trial balances to supporting schedules, propose adjusting entries where the books and the return diverge, and complete input in your practice's own return software so your adviser opens a file ready for review rather than a stack of PDFs.
Where HMRC draws the line
This is preparation support, not lodgement. Filing an SA100, a CT600, a VAT return or an MTD ITSA submission all run through an Agent Services Account, and HMRC's own new registration scheme now requires the individual acting as tax adviser to be registered too, with the first window opening 18 May 2026 for advisers without an existing ASA, SA or CT account. Our team never touches your ASA and never transmits a return; your registered adviser reviews and lodges every one.
MTD ITSA reshaping the client list
Making Tax Digital for Income Tax became mandatory from 6 April 2026 for sole traders and landlords with qualifying income above £50,000, a threshold that drops to £30,000 from April 2027. That is quietly widening the population of clients needing quarterly digital updates rather than one annual return, which is exactly the kind of recurring workload busy-season support is built to absorb.
Ramping capacity up and back down
Practices often add this support two to three weeks ahead of 31 January and taper it once filings clear, sometimes keeping a smaller version running for clients on a non-standard accounting period.
Questions
Frequently asked questions: Busy season tax prep support
Who lodges the Self Assessment or CT600, you or our practice?
Your practice does, through your own Agent Services Account. Our team only prepares the workpapers and draft input behind it.
Does MTD ITSA change what your team can help with?
Yes, in scope, not in role. We help organise the quarterly digital records MTD ITSA now requires above £50,000 of qualifying income; lodgement still runs through your ASA.
Can you work to the CT600 and SA100 deadlines at the same time?
Yes. Corporation Tax and Self Assessment workloads often overlap where a client has a non-standard year end, and capacity is scoped to cover both.
How early should we bring in busy-season support?
Most practices add it two to three weeks ahead of 31 January, though the exact ramp depends on how much prior-year file history needs reviewing first.
Can support scale down again once busy season ends?
Yes, capacity is agreed for the busy-season window and scales back down afterwards rather than becoming a fixed ongoing cost you carry all year. Practices that want year-round capacity typically move to a dedicated pod instead, which is a separate, steadier arrangement.
Does your team sign or file anything?
No. We prepare workpapers and draft input for your credentialed preparers, who review and sign every return.
Can you flex up just for filing season?
Yes. Firms typically add this capacity a few weeks before a deadline and scale it back down after.
How is busy season tax prep support priced?
Pricing for busy season tax prep support depends on your transaction volume, the software you use, and how much cleanup is needed before ongoing work starts. Current ranges are published on the pricing page, and your exact fee is confirmed in writing before anything begins.
What software works with busy season tax prep support?
Busy season tax prep support runs inside QuickBooks Online or Xero, whichever you already use. If you are not yet set up in either, we can configure a file in your name so you keep ownership of it once the engagement is under way.
Related services
- For accounting firmsReview supportA second set of eyes on files your firm has already prepared, checking ties, disclosures and workpaper completeness before they reach your partner for sign-off.
- For accounting firmsOverflow cleanup projectsFixed-scope cleanup and catch-up projects your firm can hand off when a client's books are too far behind for your own staff to absorb without disrupting other work.
Industries
- Professional servicesBookkeeping for professional service firms such as engineering, architecture and IT consulting billing clients by project or retainer.
- Startups and VC-backed companiesBookkeeping and reporting for early-stage, venture-backed companies watching burn, runway and investor reporting closely.
- Ecommerce (Amazon and Shopify)Bookkeeping for online sellers on Amazon, Shopify, Etsy and their own storefronts, built around clean payout and sales tax data.
Next step
Talk to the team that would run your books
A short call covers your setup, your software and what a first month would look like. You get a written scope and price after it.