Count of fruit bodies growing 1.6m up on the shady side of a standing dead tree. The suggested name appears to represent a species complex according to a recent thesis
There's more than one grey Resupinatus recorded from the ACT (and more elsewhere in Australia) so, based on macroscopic evidence alone, I'd not go past genus. Given the size and colour I leave this at Resupinatus. Species of Hohenbuehelia are similar but, thus far, I don't think we get such a small, grey Hohenbuehelia.