Jubilee Park at Woodhall Spa. We just came back from a weekend away 17 adults 18 kids camper vans, caravans and lots of tents. Very relaxed site, facilities basic but ok, we tended to use showers at lido. We managed to sort a few free passes too - depends which warden you get! Lots of 'flat' cycle riding on quiet roads all around, Woodhall is lovely and in walking distance.
Both Cofton county park and ladys mile near dawlish Warren Devon have really good out door heated pools the one on ladysmile has a water slide as well.
The cofton county park one is nice and is life gaurded which is good. Is also a very nice site.
Don't forget to leave a review of the campsites you have visited this year or last!