UK has a great aviation culture!
Spain 150 airfields!
UK +400!
So if you want to instruct better to train to be an instructor in the uk (more PPL culture, etc).
Spain: Vueling, Iberia, Swiftair, Air Europa (all don't hire very often), few small operators!
UK: Flybe, Jet2, Monarch, thomson, Thomas cook, British Airways, Loganair, Virgin, Eastern, Bmi regional, And all the small operators!
It's simple in the EASA world UK is the best (words from spanish PPL) !