Glad you dragged it up - I've not seen it before. Probably a waste of time saying its called "The Black Sow of Rimside Moor and the Monks of Holy Island" now, for the chap that was looking for the ballad.
Hmm. There is a whopping great chunk of stone visible on the outcrop to the west of the road as you go up past the Moor. I wonder if that's it. Might be worth a wander at some point, though the current landowner is a bit un-keen on visitors, I think it's listed as open access.