Our Self Assessment back-office services
SA100 individual returns
Full preparation covering all income sources, reliefs and allowances, ready for HMRC submission.
SA800 partnership returns
Partnership returns including partner profit-share allocations and supporting statements.
SA900 trust and estate returns
Support for executors and trustees, covering trust income, capital distributions and beneficiary reporting.
Personal tax computations
Reconciling every income stream against reliefs and allowances for an accurate final liability.
Capital gains tax
Workings for property, share and asset disposals, losses and 60-day residential property reporting.
Rental and foreign income
Property income schedules for UK and overseas landlords, with double taxation relief.
Self-employment and dividends
Accounts and tax adjustments for sole traders, capital allowances, and dividend calculations.
CIS, student loans and Child Benefit
CIS reconciliations, student loan calculations and High Income Child Benefit Charge workings.
Filing and planning
Submission through HMRC Online Filing and leading software, plus personal tax planning analysis.
Key dates
| Requirement | Deadline | Why it matters |
|---|---|---|
| Self Assessment registration | 5 October 2026 | Late registration can trigger penalties if tax is unpaid |
| Paper return deadline | 31 October 2026 | Final date for paper SA100, SA800 and SA900 returns |
| Online return deadline | 31 January 2027 | Final date for online filing |
| Balancing payment | 31 January 2027 | Remaining 2025/26 tax, due with the first payment on account |
| First payment on account | 31 January 2027 | Advance payment towards 2026/27 |
| Second payment on account | 31 July 2027 | Second advance instalment |
| HMRC amendments | Within 12 months of the filing deadline | Window to correct errors without formal disclosure |
Our standards
- Every computation checked against source documents
- Current HMRC rules, reliefs and reporting formats
- Strict confidentiality agreements and access controls
- Agreed turnaround times ahead of deadlines
- Encrypted transfer and restricted-access systems
- Organised, audit-ready working papers
- Structured review before submission
- Status updates and query logs throughout
Benefits of outsourcing
Lower costs
Avoid the salary, training and recruitment costs of temporary tax season staff.
Faster turnaround
Dedicated resourcing moves returns through preparation and review more quickly.
Scalable capacity
Flex up for January and down for the rest of the year.
More advisory time
Redeploy partners and senior staff to planning and client strategy.
Business continuity
Less reliance on individual staff during peak season.
FAQs
Frequently asked questions
Who must submit a Self Assessment return?
Sole traders, partners, directors with untaxed income, landlords, people with significant dividend or savings income, Capital Gains Tax payers, and anyone affected by the High Income Child Benefit Charge.
Will outsourcing affect my relationship with my clients?
No. We work as your back office, and client relationships, advice and communication stay with your firm.
Which tax software do you use?
TaxCalc, Xero, QuickBooks, Sage, FreeAgent and Excel-based workflows.
How secure is my financial information?
All data passes through encrypted portals and access-controlled systems, backed by confidentiality agreements and GDPR-aligned processes.
Can you help with HMRC enquiries?
Yes. We support correspondence and workings for HMRC queries, penalty notices and enquiries.
How is pricing structured?
Per-return pricing, dedicated resource models and seasonal overflow packages.