Hmmm....

This is a very very broad generalisation..

But...

despite what Mcgrath says about winter :
That's when the oldies take over isn't it? Much more likely to be folk friendly...
I'd suggest that the people of any age most likely to frequent the Costa Del Sol, may not be the people most likely to enjoy heavy doses of folk music.

I would day that out of the circle of folkies (including listeners, not just players) with whom I am acquainted, I can think of only around one person/couple who has been to Spain on a package-type deal within the past couple of years. And that was me. I had so little expectation of being able to find any folk-ish music (apart from Irish themem pubs)when I was there I didn't even bother looking.

Howevere, this is only my opinion, and I'd be interested to hear what others had to say.