We have been several times to one near Swanage, which is a great area to go with kids. The beaches in Swanage are good, and Chapman's Pool is a fantastic spot, although a bit of a walk from Worth Matravers. There is also Studland beach and a short ferry ride to the grossly over -priced Sandbanks. We use a camp site on a farm at Harmans Cross - turn right at the cross roads in Harmans Cross into Haycrafts Lane, over the railway, and turn right into the farm track on the bend half way up the hill (sorry, can't remember the name of the farm, but the camp site is signed). It is a fairly basic site - no shop or anything, just washing facilities, which are always clean. He doesn't take bookings, just turn up and pitch your tent. I have seen flatter camp sites, but it isn't too bad, there is loads of room for games and the view of Corfe is stunning.
