Evidence required of the claimant in support of the claim
167. Save as the Commissioners may otherwise allow, the claimant, before he makes a claim, shall hold in respect of each relevant supply—
(a)either—
(i)a copy of any VAT invoice which was provided in accordance with Part III of these Regulations, or
(ii)where there was no obligation to provide a VAT invoice, a document which shows the time, nature and purchaser of the relevant goods and services, and the consideration therefor,
(b)records or any other documents showing that he has accounted for and paid the VAT thereon, and
(c)records or any other documents showing that the consideration has been written off in his accounts as a bad debt.