Lucky you - we have just got back from a tour round the coast of spain and portugal in our new California - it was fantastic! We found some great campsites ( and some pretty poor ones as well!!) including what I think is the poshest campsite ever.
Anyway, back to your question, we took our standard lead with standard waterproof 240v 16amp BS4343 plugs ( these are the big blue plugs) and then a short adaptor lead that came with the california which converted from the waterproof plug to a continental 3 pin plug. We found that we had to use the adaptor on about half of the sites with the other sites either having just waterproof sockets or alternatively both waterproof and continental 3 pin sockets.
We paid around 4 euros a night for electricity so fo the sites we only spent 1 night on we didnt bother.
I hope this helps and let me know if you want any pics to make it clearer. HAve a fab time - Im very jealous.
Simon