Backdating VAT

1) If you are VAT registered and could have recovered Input VAT but didn't, yes you can go back and rewrite your books, or put in a claim. If it is a large amount, you need this:

2) If you are not VAT registered but now find that you should have been registered, then yes you can issue "VAT only" invoices to your customers and hope they will pay you. The VAT registered ones almost certainly will.

There are no restrictions on how far back you can go AFAIK.

"Troy Steadman" wrote

"Three Year Rule"?

Is there?

I've twice been back four years and over, recalculating Partial Exchange for charities who always manage to get it wrong. If you have the approval of the inspector I suspect you can do anything.