Accountants in Mortlake and Barnes Common

HMRC receives data directly from online platforms about sellers' income. If a side hustle has grown past the £1,000 trading allowance, coming forward first is always cheaper than being written to — penalties scale with how the disclosure starts.

The businesses that struggle with tax bills rarely have a tax problem; they have a timing problem. Knowing the bill in September instead of January — which filing early gives you for free — is the difference between planning and scrambling.

The first tax bill is the hardest because it can arrive with payments on account attached — up to 150% of the year's tax in one go. New businesses that save a quarter to a third of profits from day one never feel it.

The first hire brings PAYE registration, Real Time Information submissions every payday, workplace pension auto-enrolment and payslips that must be right. It's all completely manageable — as a monthly routine run by software, not a monthly crisis.

Company deadlines run off your accounting year end, not the tax year: corporation tax is payable nine months and one day after year end, and the CT600 return is due twelve months after. Confusingly, the payment is due before the return — a sequencing quirk that catches new directors.

People stay with the wrong accountant for years because switching feels disruptive. In practice the profession has a standard handover process — clearance letters, copies of prior returns and working papers — and the new firm drives it, not you.

The best salary-dividend mix moves with each year's thresholds and your other income. Setting it once in April — rather than guessing through the year — is one of the simplest pieces of planning a director can do.

If you contract through your own limited company, IR35 asks whether you'd be an employee without it. For medium and large clients, the status decision is theirs; for small clients, it's still yours — and getting it wrong in either direction costs money.