Self Employed IVA Billing To The UK

Hello,

Am looking for some advice - well, been looking for a while and cannot find any concrete answers.

Basically for someone who is becoming self employed in spain (I intend to next year) but working primarily with self employed people in the UK how does VAT/IVA charging work?

Most of the clients I will be billing are self employed in the UK without VAT numbers because of the threshold amount in the UK. If the client in the UK 'is' VAT registered it's not an issue because I can charge IVA at 0% because of the reverse VAT within the EU. But, for self employed people in the UK who do no need to be VAT registered what happens? Adding VAT (IVA) to their billing is confusing to them as well as bumping up the price. It's confusing to Spanish accountants and gestors because many don't seem to understand that you don't actually need a VAT number unless you are over an earning threshold - unlike here in Spain where you have to have one before submitting an invoice.

Any advice from anyone in a similar situation would be appreciated.

Thanks - Andy