Ooh don't think i can choose ! They really are all lovely At the Tansley one...kids just seemed to play together more (badminton and bikes that sort of thing)..because of the lack of play area. It was very quiet and if you go non ehu..you can pitch amongst the pines...it was really pretty. Also great stuff nearby. The Robins hoods bay one is amazing..you walk through cow fields and a nature trail down to the beach. Near Whitby too and North York moors. Lime Park is lovely too (beautiful viaduct and surrounding area)..the main tent field is rather steep though...i've only camped in the top field which i mostly campervans.The facilities are absolutely spotless
Kingsbury Water Park has all the things you're asking for....is only just out of south derbys. Rubberduck has been, says its fab, and close to west mids for lots of other activities, inc thomasland if your dc are that way inclined.
We've stayed at Bainland Country Park in Woodall Spa with caravan and trailer tent. Has small indoor play area, outdoor play area, bar, small swim pool, good clean toilet blocks and you only about 40 mile from skeg/mablethorpe.