I found unmistakable cup marks a month or two ago at this site...
http://www.themodernantiquarian.com/browse.php?site_id=3657
...that I can find no reference to in any of the local literature. I guess none of you will believe me without photos though! : (
I'll be contacting Stan (who is a friend of my Grandmother's and often to be found drinking her tea & eating her cake) about it in the near future. I'm holding off for the time being, though, cause I need to get back up there with my camera. I think it very likely that there'll be more rock art very close at hand, too, so I want to explore more fully before I get in touch with him.
Pictures coming soon, is all I can promise...