We had our first extended trip this year (December - March). Fopund Northern Spain a little cooler in January so went on down to the Costa del Sol. Many of the sites on the coast there there are overcrowded and have a lot of 'shanty town' type permanent placements .
We found a good CL type smaller site about 30 minutes inland from Marbella,Malaga and the other major resorts.
http://uk.geocities.com/fincadelapiedra/ They only take about 5 or 6 vans but are very helpful, and the site has excellent shower & toilet facilities, sensible electricity around 16A I think, free Sky Hook Up if you bring your box and Internet Access.
It suited us and we had a couple of months there. be happy to share my album of the area and pass on other information regarding our own experiences.
We are thinking of trying to organise a small group to go back this winter.
If you have any specific questions then maybe we can arrange to swop contact details somehow
Nick