In reply to BarrySW19:
This is simple. The Spanish NHS does not treat serious sporting injuries free of charge, even for Spanish people, which is one reason why there is a a strong culture of national sports federation membership in Spain, which come included with medical insurance to cover any invoices from their own NHS !
There is also the other issue of some land owners and national parks requiring thrid party cover by climbers on their land.
Get insurance and in the unfortuate event of a serious injury, get back to the NHS as quick as possible.
Mountain rescue in Valencia/Alicante/Murcia is free, as far as I am aware.