what paperwork is needed when taking 8 year old from a uk school to a school in spain?

Answer 1

Ask the specific school to make sure.

You need health records (proof of the right shots being taken), school records (proof of attendance, perhaps levels of achievement), and occasionally they'll want the school to transfer details of the child's character (which may be kept hidden from the parent).

Sometimes the school can do this themselves if you sign a release form.

And remember, the different regions in spain are semi-autonomous, and can make some of their own rules.