He he - thanks Doug.  Have now come across another invoice, also concrete but different supplier, that has £410 + £94 VAT = £504!!   Client has paid £504 so it's back to the supplier for that one.  This VAT return isn't as concrete as I thought it was!!

Where it's an invoice to be paid, I do exactly that; if I receive an invoice that shows VAT but lacks a VAT number, I post the net and VAT into my software on two separate lines and mark the VAT on hold temporarily. I then send them an email notifying them that the VAT will not be paid unless they supply an updated invoice showing their number, or the number itself for me to add to the invoice. (With that link and a reminder that they need to fix their invoices to make them legal).

If they reply with their VAT number, I'm happy to manually add it to the invoice because (a) I can check it via VIES (at the moment*) and (b) the emails show that I have asked for it and it has come from them.

I have a template email for that purpose - which should give an indication of how often I need to do this!

Off the top of my head, I'd say about 10% reply with an updated invoice or their number, and probably a similar number, having ignored the email, chase for payment of the missing VAT, at which point they have to supply the necessary before it's paid. The rest never follow up, so when VAT return time comes, I post a credit for the VAT so the client isn't claiming something back that's clearly not valid.

However, that's for an invoice that needs to be paid... John's talking about a receipt. I've never had that scenario. I reckon I'd still be inclined to contact the supplier, but I suspect that because they already have the money, it'll be harder to make them comply, so I'd probably also find the number from other sources and add it to the receipt (but checking it via VIES and showing my working - e.g. a print out of the page.)

And the one that's calculated incorrectly? This I do see occasionally, usually on invoices from Amazon marketplace suppliers - thankfully, not often and only small amounts, though. I've always corrected the VAT based on the invoice total (after first checking their number is valid) - but I suppose there is an argument that says claim back the (incorrect) amount they specify, because that's what they've presumably declared and paid.