There is one in Tewkesbury called Croft Farm water park . It is quite busy, and a half way house between a large all singing and dancing site, and one with not much facilities. They have a small lake for watersports, own boats, hire boats and canoes.
I went there with my husband and 5 year old a couple of years ago. It was quite child friendly for 5 up, I would say. It is a mix of statics and tourers.
http://www.ukcampsite.co.uk/sites/details.asp?revid=1811
Feezee
------------- -------------
Took a break like everyone over covid, flogged the caravan and got a campervan!
Hoburne Cotswolds, near the Waterparks just outside Cirencester is an option.
They have a swimming pool indoor and outdoor, tennis courts, playground, small soft play, bar with entertainment if thats your thing. Also fishing on site.
------------- 2015 sites booked so far: Cotswold Farm Park, Ninham IOW, still some more to book