Just a quick word for Santander as a point of entry to Spain based on experience 2 wks ago.
Very efficient, fuel delivered to the aircraft on arrival (Cash or fuel card only), customs at the airport (don't know about notice required as I routed from France), met and flight plan filing in flight briefing unit and no delay on departure after filing flight plan. Very good
Spanish AIS site with airport info.
Total bill for 2 days parking and landing: 7 Euros.
Car hire and tourist info in the airport. Tourist info very helpful but car hire v. expensive (100 Euro for 1 day!) doubtless better to book on t'internet. Taxis relatively cheap though.
Wonderful scenery and fabulous beach at Somo around the bay.
Just out of range from Wellesbourne (5.5 hrs approx) but very practical with a stop in CI where apparently the fuel is cheaper, or even if you can afford the landing fee direct from Bournemouth.