Hey up KK,

I'm afraid I can't be much help with your stone.
'S been sometime since I was last up that way but I don't think it's a stone I've come across.

The possible cup marks look interesting.....Although I've gotta admit to being very wary about thinking along them lines because of the Eastern and Dark Peak Moors 20th century military training history, in particular those ones close to Sheffield.

nice one
stu.