There is some very good information on general dormouse ecology, habitat management and dormouse science at www.greenboot.co.uk
Peoples Trust for Endangered Species manage the National Dormouse Database (NDD) and the National Dormouse Monitoring Programme (NDMP) and co-ordinate much of the conservation work on dormice in England
The Mammal Society organise training courses to help interested people work towards their dormouse licence.
Surrey Dormouse Group – contact Dave Williams of Surrey Wildlife Trust
Sussex Dormouse Group – contact Penny Green of Sussex Records Centre
Kent Mammal Group – contact Hazel Ryan of Wildwood