If floors count, then there's this one too:
http://rockart.ncl.ac.uk/panel_detail.asp?pi=750
Though it's not concreted, technically, this one is in a wall:
http://rockart.ncl.ac.uk/panel_detail.asp?pi=757 just in it's own (purpose built?) niche.
Apparently, there's a bona fide cup mark in somebody's fireplace mantleshelf in Cumbria somewhere. Peer-reviewed and everything (wooo!).