Yes I know, almost as rare as an SP paying Income Tax, though I think more of 'em are wised up to that tax issue these days. My particular fave girl was hauled over the coals a while ago on Income Tax but VAT was not an issue since her total income was below the registration level for VAT.
As prices go up so does the possibility of a VAT liability arising.
Remember, the VAT was put under the purview of Customs and Excise originally. Those chaps had powers way above the then powers of the Inland Revenue as it was.