I like the sound of HMRC's proposed VAT amnesty. We could well have a few candidates.
I am sure most practitioners have a few, sole traders that manage every year to keep JUST below the registration threshold. Having said that, one of my oldest clients has done this for years, but I know him personally and I am confident there's no VAT at stake - he doesn't need a big income, so if he has a few good months he simply stops working and spends his time fixing up his old house or doing voluntary work!
But I do have a few others who need to be pressed this year to consider whether in fact they may have been over the limit but, shall we say, massaged the figures. And I do have one who regularly posts turnover over the VAT threshold on his SA tax return but has never registered for VAT. Clearly the income tax and VAT sections don't talk to each other or they could identify quite a few potential miscreants instantly.