Re: Wild camping in south east England.
There are little nooks you can camp in on the South Downs. But , your problem is that you will have to take all your water needs with you - no running streams at all, and as has been said, camp late, and break camp early. i have been walking on Butser Hill at 8am on a sunday morning.........and have met at least 4/5 people out walking their dogs.
Therein lies the problem. The downs are so bloody accessible for anyone who lives in them. not much height to gain before you're on the top ridge. So you will always be in danger of discovery by the wrong person.
Having said that, with a little ferreting around, I'm sure you could find somewhere out of sight and away from the paths which litter the place. I'm thinking of Beacon hill......maybe the south facing long slope...there are copse', and "bottoms" aplenty, where you could nestle down. Once again, you WILL be trespassing, as all the land is owned by local farmers, who are not very far away.
Personally, I wouldn't camp ton the South Downs. I'd always be twitching at the slightest sound. But, maybe you'd enjoy the thrill of not being discovered.
"Well, I'm standing next to a mountain........an' I chop it down with the edge of hand........huh, huh"