I'm not sure about recent developments in East Sussex, but I was researching a form of off the grid living known as 'Earthships', or Earthship architecture, sometimes known as Biotecture. Check out 'earthships' or 'mike reynolds' (architect) on youtube, I'm pretty sure they had a channel.
There were only two places which had working Earthships actually built in the UK, one in Scotland somewhere, one in Brighton, where they also run short courses on how to build the things. Definately worth checking out.
Let me know if its any help.
"Do nothing which is of no use" Musashi Miyamato