Schools/Teenage life

Hello, we are a family of 4 from Scotland, two kids aged 11 and almost 8. We are planning to move to one of the Canary Islands in summer 2020. We don't want to move anywhere too quiet - we want the kids to make friends and are thinking ahead to the teenage community - we want teenagers to have lots to do and friends tto go places with.

We also need advice on schools. We feel that our older child, who will be starting secondary when we move, is too old to enter Spanish education with the view to sitting exams in a few years, as he may struggle with the language. Our younger child we feel can be put into a Spanish school at her age and she will have plenty of time to pick it up.

Our questions are :

What reasonably priced good British secondary schools are there on any of the islands?
What island/area of an island would you recommend for a good teenage life?

Thanks in advance.