Can vat be charged for previous payments?

[Lizzybenette7]

Hi all, new to the forum. Not sure whether this is the right place to ask. Having domestic construction work done. Paid 3/4 in cash with promise of vat discount. 1/4will be paid once work is completed. Now builder wanted to add vat on previous and remaining payments. Builder is vat registered. No vat mentioned on quotation. No vat invoice/receipt so far. Where do we stand? Many thanks in advance

[pawncob]

It's a legal question, not taxation.

[bd6759]

Depends if you are a consumer or a business.