Walter Segal, a German émigré architect who settled in Britain, developed the Segal Method of timber construction to help enable cheap timber buildings to be constructed by non-professional self builders. The early projects were mainly in Lewisham, South London and the Walter Segal Self Build Trust continues to promote the approach to the public. A number of projects can be found on their website here.
Making Lewes 
It would be amazing to see a Walter Segal Co-housing project in Lewes as part of the development in the center of the town. There would need to be some thought about how the house would adapt to flood risk? Recent news and images of flooding at Somerset Levels (highest rain fall for over 100 years) bring home the risks for developing the land near to the river! Does anyone know of developments that adapted to cope with flooding?