When exactly are you allowed to call money "revenue"? It's not when the cash arrives, and it's not when you win the deal. Getting this wrong makes your numbers lie to you.
Two ways to keep score. Cash accounting records revenue when the money lands. Accrual accounting records it when you earn it, by delivering the work, regardless of when you're paid. Most real businesses run on accruals, because it matches income to the work that created it.
The rule of thumb: you recognise revenue when you've delivered what you promised and you can reasonably expect to be paid.
A £12,000 project delivered over three months? You recognise about £4,000 a month as you deliver, not £12,000 on day one.
Deliver in stages, recognise in stages.
Recognition isn't a feeling; you need evidence. A signed contract or SOW, proof the work was delivered, client sign-off or acceptance, and a clear basis for the amount.
Without proof, you're not recognising revenue; you're guessing, and an auditor or an accountant will unwind it.
Recognise revenue as you earn it, with evidence behind every number. It keeps your P&L honest and your margins real.