Campsites easily reached on public transport?

[MackerelOfFact]

We love camping, but living in London without a car (or license) we only get to camp at festivals or on land owned by people we know, who can offer a lift.

It'd be great to camp over the August bank holiday. Aside from Crystal Palace (which is only about a 20 minute walk from where we live) is there anywhere nice that can be reached fairly easily from London by train, ideally walkable from a station? Sussex and Kent are particularly easy for us to get to, but would consider anywhere!

Hollands Wood in the New Forest is walkable to from Brockenhurst station (around 20 minutes I think) You would need to book ahead at this time of year. It is a busy site, but set in woodland and you have to watch the raiding ponies with food.

Ooh that looks perfect, and really easy to get to. I'm probably pushing my luck for August Bank Holiday though, I know.

The Caravan Club Norman's Bay site is v close to the station, and right on the beach. It is a very 'straight lines and no fires' kind of site, though a very nice one.