Hallo Mac,
I've not been there, though I've often scrutinised it on Google Earth. On a couple of occasions, myself and another tma contributor, Mr Rockandy, have discussed the need for a visit. The circular features that are so visible on the satellite images, combined with the reports of cists, combined with proximity to sites like Bunkerhill and Hunetrheugh, combined with the presumed view of the Cheviot massif, all add up to suggest a likely spot for some rock art. So those cups you found could be the real deal.
I've posted a comment on your notes, and another on one of your pics, relating to the 'hole' feature. Which I'd no idea was there, but am intrigued to hear of it's existence.
I'm really not sure what to make of those circular erathworks though. 'Tree rings'? What are they? Yet they all look to be a bit crowded, and a bit pristine, to be the banks of some kind of bronze age cemetery.
All power to your elbow Mac :)