Here are some links to other organisations which you may find useful:
Fungus Conservation Trust (formerly the Association of British Fungus Groups)
The British Mycological Society
The European Mycological Association
Myxomagic – a site devoted to Myxomycetes and othe wildlife
Cotswold Fungus Group (see also their Facebook page)
Herefordshire Fungus Survey Group
North Somerset and Bristol Fungus Group
Gloucestershire Wildlife Trust
Gloucestershire Naturalists’ Society
Natural England (formerly English Nature)
i-Spot (photo identification)