Any offers for this one:
My belief is that it is in the Lentinellus genus, either L. vulpinus, or L. ursinus. Unfortunately I was tired and bored at the time, and only by chance took a photo, but no sample. My brief notes are as follows:
"Ashridge Forest 9 October 2006
Large oyster fungus in clumps on fallen Beech Cap 5-12cm flesh colour surface textured margin with coarse white scales. Gills whitish. Stem short or absent, lateral, dark brown. Smell pleasant fruity. Flesh tough."
The smell and lack of a woolly cap surface suggest Lentinellus ursinus, but it is very rare, apparently known only from three counties including Bucks where the above species was found.
Incidentally, species in the genus include L. vulpinus, L. ursinus, L. tigrinus and L. castoreus. I think someone was having almost as much fun as the person who came up with the BMS recommended common names.