Well the advice over export slips has varied over the years from yes we want a slip back, to no a letter will do. It doesn't really matter as long as they are notified in some way.
However, the current procedure is at the bottom of this page: https://www.gov.uk/responsibilities-selling-vehicle
Taking the vehicle abroad and registering it there
- Fill in the ‘permanent export’ section of your vehicle log book.
- Send it to DVLA, Swansea, SA99 1BD. Include a letter giving the buyer’s name and address.
- Give the rest of your log book to the buyer - they’ll need it to register the vehicle in the country they’re going to.
You’ll usually get a refund on your vehicle tax in 4 to 6 weeks. The refund is worked out from the date DVLA gets your ‘permanent export’ section.
You don't need the whole
2-page V5C either, the second page is just slips. The first A4 sheet is fine - the one that has all the vehicle details on.
Front of the first sheet:
Rear of the first sheet:
Current red ones no longer show the previous recorded keeper (GDPR nonsense). I think the older blue ones are still valid (but watch out for dodgy ones) and the really old pre-V5C documents (V5 Vehicle Regsitration Document - not EU-friendly V5C Vehicle Registration Certificate) are no longer valid.