Beckensall's British Prehistoric Rock Art has a photo on p55 of an earthfast boulder at Eel hillBarningham moor, it has cup and rings and a extra big cup.
A quick look at
http://groups.msn.com/rockartinthebritishlandscape
didn't show owt.
When does the diameter of the hole stop it being a cup and make it something else?
lamps to carve motifs at night?