Sandymouth Holiday Park in Bude, Cornwall. Just got back from there last week. Very clean, stuff to do (all age ranges of kids seemed to have a great time), entertainment is on the right side of tacky & the food in the clubs reasonable & tasty (not everything is 'n chips). Less than a mile from a gorgeous beach. Put it this way, we're going back next year & we NEVER normally revisit places.
Hi - you could try a caravan or lodge at one of the Hoburne sites. there are 3 in the the new forest area. they are clean & well kept, have indoor & outdoor pools, play-grounds, childrens entertainment team, club-house with restaurant & evening entertainment. there is loads to do in that area especially for boys, cycling in the forest - you can hire bikes. fishing & crabbing off the beach or quay. cheap day trip to isle of wight as foot passenger from Lymington. Hurst castle, Bournemouth, etc.