good books are
Wild Food by Roger Philips
Food for Free by Richard Mabey
I'd suggest also buying a good botanical key to make sure you are picking what you should be picking!
There is plenty of wild garlic about also.
if you're looking for survival schools / bushcraft schools then try - http://www.bearclawbushcraft.co.uk
also, keep an eye out for road kill - at Christmas my girlfriend found a recently hit Roe deer (it was still warm) and she gutted it, and we both skinned and butchered it - we got just over a stone of good quality venison off it. Lovely stuff. Plenty of Rabbits and Pheasants get hit also - so well worth it
what the thinker thinks the prover proves.
Make the world work, for 100% of humanity, in the shortest possible time, through spontaneous cooperation, without ecological offense or the disadvantage of anyone.