Documents needed to matriculate Uk car to Spanish plates

You’ll need to have the car ITV’d first, so obtain Ficha Técnica, change headlights etc, then DGT to get plates - I’m not certain who collects the import tax.  AEAT would be the authority responsible but likely it’s collected on their behalf … and I’m not certain at what point import tax is collected - I just know you need to have your ITV before you can matriculate your car

If you contact car-registrations-spain, they are on Facebook, with your registration number they will give you a price for everything. They can remanufacture most headlights and other lights instead of replacing, ITV, etc. I took mine there for 1000 one morning and all finished by 1400, new plates arrived about 10 days later and they speak English.

Good luck.