Also If you wear glasses then you must carry a spare pair in the vehicle when driving in Spain. This means anyone who you allow to drive the vehicle as well must carry a spare..
The "official" law in Spain is 2 hi-vis vests, Driver and passenger.. However the practised law is one vest for each occupant.. So I always carried 5..
In france and other euro countries you must have a fire extinguisher..
So really the rull of thumb is this for the whole of Europe.
1: Spare bulb kit (correct for you vehicle)
2: Hi-vis vests, 1 for each occupant (as detailed on your registration document)
3: Two warning triangles. Eu approved! (especially in spain, the Guardia can be hot on this)
4: Fire extinguisher
5: First aid kit
Carry the vehicle documents with you.. Ie, Registration doc, Insurance certificate / Green card (including a receipt that shows the policy has been paid for to cover spanish laws), MOT certificate.
In any case have a nice holiday..