Filing-ready, prepared by people who already know your books
Tax preparation support
Finbryn provides preparation support for UK tax returns: Corporation Tax (CT600), Self Assessment (SA100), VAT under Making Tax Digital and Making Tax Digital for Income Tax. Every figure is built from reconciled books, then reviewed and lodged by a registered agent under HMRC money laundering supervision before anything reaches HMRC or Companies House.
Tax working papers
Illustrative client · August 2026
GBP
- Year-end books closed and reconciledDone
- Fixed asset and depreciation scheduleDone
- Book-to-tax adjustments listedDone
- Supporting schedules for the preparerIn progress
- Handed to the signer for review and filingNext
Illustrative. An example of the document, not a client's figures.
Preparation support, filed through a registered agent
Finbryn provides preparation support for UK tax returns. We build the return from your bookkeeping, contracted through Northlane Solutions Inc.; a registered agent operating under HM Revenue & Customs money laundering supervision reviews and lodges it. We do not sign or transmit anything ourselves, and we say so plainly, because the rules on who may act as a tax adviser or file for a client tightened materially in 2026.
What changed in 2026
HMRC's mandatory tax adviser registration scheme opened its first phase on 18 May 2026, and its final phase, covering advisers who already hold an Agent Services Account, runs from 31 December 2026 to 31 March 2027. Anyone acting for a client without the right registration risks losing the ability to interact with HMRC at all. Every filing we support is routed through your own UK agent holding that registration, or a partner adviser we introduce once that partnership is signed.
What we cover
Corporation Tax computations and the CT600 return, Self Assessment (SA100) for directors and sole traders, quarterly VAT returns filed under Making Tax Digital, and Making Tax Digital for Income Tax, mandatory from 6 April 2026 for sole traders and landlords with qualifying income above £50,000. We also prepare the workpapers behind Companies House filings, though the filing itself sits with an Authorised Corporate Service Provider once that regime is fully in force.
Built from books already reconciled
Corporation Tax and VAT figures start from the same monthly close our bookkeeping team already produces in Xero, QuickBooks Online, Sage or FreeAgent, with receipts captured through Dext or Hubdoc. Because the numbers already tie out before filing season starts, a return is rarely a scramble.
Standards and deadlines that apply
We work to FRS 102 and FRS 105, including the Periodic Review changes to FRS 102 effective for periods beginning on or after 1 January 2026. A Company Tax Return is due 12 months after the end of the accounting period, while Corporation Tax itself is due 9 months and 1 day after that same period end, an earlier date than most directors expect.
Working from your reconciled books
Northlane Solutions Inc. is the company you contract with, and your data is handled under UK GDPR and the Data Protection Act 2018. See monthly bookkeeping if your records are not yet reconciled, pricing for what preparation support costs, and how it works for onboarding.
All services
Tax preparation support: every service
- Tax planning supportYear-round planning support that looks ahead of filing season, modeling entity structure, timing and elections so decisions get made before a deadline forces them.
- Corporation tax return preparation supportPreparation support for a limited company's corporation tax return and computations, built from statutory accounts and reviewed by a credentialed signer before filing.
- Self assessment preparation supportPreparation support for an individual's self assessment return, including directors and sole traders, reviewed by a credentialed signer before filing.
- VAT return preparation support (Making Tax Digital)Preparation support for quarterly VAT returns filed through Making Tax Digital, built from digitally linked records in your accounting software.
- Making Tax Digital for Income Tax supportPreparation support for the quarterly updates and end-of-period statement required under Making Tax Digital for Income Tax, built from digitally kept records.
Questions
Frequently asked questions: Tax preparation support
Do you file my UK tax return yourselves?
No. We prepare the computation and draft return. A registered agent holding an HMRC Agent Services Account, supervised under the money laundering regulations, reviews and lodges it.
Is my data handled securely?
Yes. Your data is handled under UK GDPR and the Data Protection Act 2018, and Northlane Solutions Inc. is the company you contract with for the work.
What UK filings do you support?
Corporation Tax (CT600), Self Assessment (SA100), VAT under Making Tax Digital, and Making Tax Digital for Income Tax.
Who is the registered agent that actually lodges filings?
Your own UK agent holding an HMRC Agent Services Account, or a partner adviser we introduce once that partnership is signed. We tell you which before work on any return starts.
Do you also handle our bookkeeping?
Yes, clients often start with monthly bookkeeping so the tax figures are already reconciled before a filing deadline arrives.
What is out of scope for tax preparation support?
We prepare the figures, forms and supporting schedules for your Corporation Tax return, Self Assessment or VAT return. We do not sign, file or lodge anything with HMRC ourselves, give formal tax advice that requires a registered adviser, or represent you in an HMRC dispute, all of which sit with a credentialed signer or partner.
What is the handover once a return is prepared?
A completed draft return with supporting schedules and workings, ready for your credentialed signer or registered agent to review, sign and file with HMRC. You also receive the underlying reconciliation, so the numbers on the return trace back to your bookkeeping without a separate review from scratch.
How is pricing structured for tax preparation support?
Pricing depends on which filings apply, Corporation Tax, Self Assessment, VAT under Making Tax Digital, and how complex the underlying records are, not one fee for every business. Tax planning work is scoped and priced separately, and terms are confirmed in your engagement letter before the return is started.
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.