If you work under the Construction Industry Scheme, 20% is taken from your payments before you see them and nothing in that deduction accounts for your allowance, your tools, your van or your travel. Most subcontractors are owed money by the time the year ends. We file as soon as the tax year closes rather than waiting for January, which is the single biggest thing that gets a refund back sooner.

The N20 stretch is trades and small limited companies more than retail: builders and subcontractors, contractors on day rates, and owner-managed companies with a handful of staff.

For subcontractors the recurring issue is the twenty per cent deducted at source, which usually means a refund rather than a bill — but only once the return is filed, and the deductions are only credited if the statements were kept. For contractors it is status, which is decided by how the work is actually done rather than by what the contract says.

• CIS and construction subcontractors
• Contractors and IR35
• Limited company accountant, North London
• Accountants in Barnet
• Accountants in Finchley

The trades are the largest single group we act for around Whetstone and the High Road, and three questions account for most of what we are asked. None of them is complicated. All of them are routinely got wrong in a way that costs money in both directions.

A van is treated very differently from a car

For a company vehicle, the benefit-in-kind charge on a van is a fixed amount and the charge on a car is a percentage of its list price based on emissions — which for most vehicles is a much larger number. The classification depends on how the vehicle is constructed and what it is primarily suited for, not on what it is called. Double-cab pick-ups in particular have caused expensive surprises. Check before purchase, not at the year end.

Tools and equipment

Tools bought for the work are deductible, and where they are a capital item they usually attract full relief in the year of purchase under the annual investment allowance. What causes trouble is the item with a genuine private use, and the item bought before the business started. Both are claimable, with adjustment — but only if the records show which is which.

Mileage: the two methods do not mix

You can either claim a flat rate per business mile or claim the actual running costs with capital allowances — not both, and once you have chosen for a vehicle you generally stay with it for as long as you have it. The flat rate is simpler and often better for a lower-value vehicle. Actual costs tend to win for an expensive or heavily used one. The mistake is switching casually between them, or keeping no mileage record at all and estimating, which is the first thing an enquiry asks to see.

Most trades in N20 are sole traders, not companies, which puts them in the path of Making Tax Digital for Income Tax. Since 6 April 2026, sole traders whose qualifying income is over £50,000 have had to keep digital records and send HMRC quarterly updates. The threshold drops to £30,000 from April 2027 and £20,000 from April 2028.

For a builder or electrician the key point is that qualifying income is turnover, not profit. A job that is mostly materials still counts in full. So does a CIS payment where 20% was deducted before you saw it. Many tradespeople with ordinary profits are therefore over the line. The practical change is that receipts need to be recorded as you go, not handed over in a carrier bag once a year.

Whetstone is in the London Borough of Barnet, and our office is three stops down the Northern line. For the rest of our local work, see our pages for accountants in Finchley and accountants in Barnet, or accountants in North London for the wider area.

• Accountants in Finchley
• Accountants in Barnet
• Accountants in North London
• Making Tax Digital for individuals

From Totteridge & Whetstone station it is three stops south on the Northern line — Woodside Park, West Finchley, then Finchley Central — and a short walk from there to Regents Park Road.

By bus, the 125 and the 326 both run from Whetstone to Finchley Central.

You do not have to come in: you can work with us entirely by phone, email and video call, and we respond within one working day.

Whetstone is in the London Borough of Barnet, so Barnet Council sends your business rates bill and deals with premises licences, street trading and planning. None of that goes on a tax return, but rates are a fixed cost that can be relieved or appealed, and licence fees and timings belong in any plan for opening or changing premises.

The N20 postcode lies wholly within Barnet. The units along the High Road are mostly small, and the rateable value and relief position are worth checking each time a lease is renewed, not only at the start.

Small business rate relief is set nationally and applied by the council: a business with one property whose rateable value is below £15,000 can get relief, and below £12,000 the relief is 100%. Taking on a second property can take it away from the first, so it is worth checking before you sign a lease rather than after the bill arrives.

• Barnet Council: business rates
• Barnet Council: business rates discounts, exemptions and relief
• Barnet Council: licences, permits and registrations

The services we provide in Whetstone include personal tax and self-assessment, bookkeeping, VAT returns and registration, payroll and year-end accounts and corporation tax. Each has its own page with what is included and how we work.