Here's a very interesting and useful response to my amateurish attempts to identify this fungus which I photographed on the Stray, from my friend David Swindell:
"Without a doubt it's inkcap, Toni, one of my favourites, unmistakeable. If smooth rather than shaggy you shouldn't drink any alcohol with them - won't poison you, but might make you feel very ill - used in cures for alcoholics. We once gathered pounds of them in Andover, and in the Falklands they tasted a little bitter. The condition of the ones you photographed is perfect for picking. Don't wash them, peel them if you must though that isn't necessary either, split down the middle and fry gently in hot, garlicked butter."