for londoners this is a great place
debden house camp site in the epping forest
http://www.debdenhouse.com/index.html
camp site has 7 fields each for different users, for families for young people, camper vans etc. prices are reasonable. facilities good and clean. tents, tarps hammocks and fire is allowed. we went to 2. field, that was the most foresty. don't purchase fire wood from the site, it is cheap but crap.
there is no fence around the site so u have straight access to epping forest.
spent a weekend there with the family, we had a good time, i recommend this site.
i made a short video about our weekend:
[video=youtube;JT_r9XAriN0]https://www.youtube.com/watch?v=JT_r9XAriN0[/video]