Oyster Mushroom

I found what I think is a cluster of Oyster mushrooms growing on a fallen silver birch last Saturday. They've survived reasonably well, although nibbled a bit by slugs. The gills are decurrent and the stem is eccentric (that is, off centre). The oyster mushroom is so-called because of its fan shape and cap colour rather than the taste. It is edible and is widely cultivated for sale. As ever, if I've got the id wrong, do let me know.