I found Allianz who have offices and brokers throughout Spain to be very good. Have both my van and house insured with them. You only know how good they are when you need to use them. I had an accident in my van and their service was fast and effective. Next door got hit by lightning but did damage to our property, including total loss of power, they had an electrician out within 2 hours and were very helpful with the further damage claims we needed to sort out. They have English speaking staff in their call centres if you need it too.
Two thumbs up from me definately.