We like Merley Court. Granted it is not cheap, but IMO it has the best of both worlds for what you want, it has an onsite pool, kids play area, shop and small bar/ restaurant. You also have free passes for the other Shorefield sites (one is a 5 mile drive away) for the full on pools and entertainment package, yet you can then return to the (relative) peace and tranquility of your site. The back of the site also leads out to a park from which you can cross the road to an old railway line cycle path if that is your thing.
Litton Lawn (same group) offers the same, but I have not been there so I cannot comment.