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Cohort N° III Contractors, IR35 & CIS
N° III / VI · Cohort

Contractors, IR35 & CIS

PSC contractors and CIS subcontractors working across Bristol, Severnside and the South-West.

IR35 status reviews CIS300 monthly returns Gross-payment status CIS reverse-charge VAT
Overview Overview

Two contracting populations sit here, each with their own determination problem. PSC contractors on inside / outside-IR35 engagements with Bristol corporate and Severnside operators — the reforms shifted the determination burden onto end clients in 2017 (public sector) and 2021 (private sector medium & large), but the underlying rules and the financial difference between inside and outside remain stark. CIS subcontractors — trades and labour-only operators paid through the Construction Industry Scheme, where every payment lands net of 20% (verified) or 30% (unverified) deduction. We review each contract, document working practices, hold the SDS where appropriate, and on the CIS side we register subcontractors, pursue gross-payment status where eligible, file the monthly CIS300, and reconcile deductions against year-end CT or self-assessment so what was withheld actually credits through.

Working Rhythm

The shape of a
year with us.

Contract review on every new engagement — working practices documented, Status Determination Statement reviewed, evidence of mutuality (or its absence) collected from week one rather than reconstructed under enquiry. Monthly (CIS): subcontractor verifications run, CIS300 contractor return filed by the 19th, deduction statements issued to subcontractors. Quarterly: confirm the IR35 practice has held, no project drift toward inside-IR35 indicators; for CIS clients, gross-payment-status compliance test re-run before HMRC’s. Annually: salary / dividend split optimised for that year’s rates, CIS deductions credited through CT600 or SA100 properly, plus the personal tax return.

Pitfalls Where it goes wrong

The mistakes a
generalist misses.

Each is something we’ve seen multiple times in inherited engagements — and something we now check for as a matter of course.

  • N° 01

    An end-client SDS taken at face value without reviewing the underlying working practices — a determination is only as defensible as the evidence behind it.

  • N° 02

    The ‘mutuality of obligation’ question conflated with the contractual right of substitution — both matter, separately, and inside-IR35 risk lives in either gap.

  • N° 03

    CIS gross-payment status lapsing without warning — a single late tax payment in the qualifying period and HMRC withdraws it, restoring 20% deductions on every invoice for the next twelve months.

  • N° 04

    CIS-VAT reverse-charge missed on construction services from March 2021 — subcontractors invoicing main contractors owe the VAT under reverse charge while the CIS deduction still applies on the labour element. Both rules at once trips up most bookkeeping setups.

  • N° 05

    CIS deductions sitting on the books unclaimed — the subcontractor paid HMRC but never credited the deductions through the SA100 or CT600, leaving a five-figure asset stranded.

  • N° 06

    Dividends paid quarterly out of habit, ignoring the dividend allowance now at £500 and the basic-rate band that the income-tax thresholds quietly froze.

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