For years my family had a static caravan at a beautiful site in the New Forest (Hampshire/Dorset). The site is called Bashley Park & is part of the Hoburne Group.
There is a clubhouse with indoor & outdoor swimming pools, take-away restaurant, bar, games room, arcade, tennis courts, adventure playground, golf course, childrens club (Sammy Seahorse), evening entertainment etc. It is close to beaches, lots of lovely shops, restaurants etc. There is lots to see & do in the area.
There are also 2 other sister sites within a few miles of Bashley, there is the main Hoburne Park & also Naish.
Here is a link to the site where you can find out about availability & prices.
You cannot hire out a static van directly through Bashley Park anymore as they are all owned privately (I think you can with the other sites), but I can get hold of some numbers for you if you are interested in that particular site. TBH, it is definitely the best off all the Hoburne sites.