We spent 10 days weeks at Camping Playa de Oyambre (www.oyambre.com) nr Comillas in Cantabria this August. The site takes caravans, tents & motorhomes and there are a limited number of wooden chalets for hire. The site is an easy journey of about 50km west of Santander, about 50mins with our caravan on the back. We caught the ferry from Plymouth to Santander.
The site appears to tick your boxes, it has EHU's (2 pin adapter required), is near to a fantastic beach and has a restaurant onsite. If you want to go out elsewhere though you will need to go to either Comillas or San Vicente del Barquera which are a few miles in each direction and have lots of excellent restaurants.
The site is very well maintained with the toilet block seemingly constantly being cleaned, it has a great outdoor swimming pool, play area and 5-a-side football pitch which was very popular with our boys. It's a large site (600 units) and you are typically close to your neighbours but it's not noisy and at midnight the majority of the site lighting goes out which is a very effective way of saying bedtime!
The owner Francis is brilliant, always on hand to help he watches carefully over his site, always walking around to make sure all is OK, shows you to your pitch and gets help to manouvre your outfit if required.
I thought it was good value too - 9 nights for us all inc EHU, awning etc was about _340. We found living costs comparable - diesel (_0.86) and food in supermarkets was generally cheaper than UK.
The fery crossing was excellent but not cheap (car + caravan + 2 adults + 3 kids over 5 =