Sorry - I meant to reply before! I think that if you were subject to a VAT inspection, they would be able to get at your PC anyway. HMRC already have huge powers. Don't get on the wrong side of them!!!

(On the other hand, I know someone who, dissatisfied with the work a cowboy builder did, tipped him off to the Customs and Excise who lokoed after VAT back then: not something to wish even on your enemies!)