It's worth looking up the refs on the ERA site, I know the res of the maps is a bit on the low side, but the numeric data is spot on. If you use the ERA numeric refs and enter then into a random GE pin, they'll tell you exactly where everything is. The grouse butts are useful waymarkers on your way from the parking spot up to the carvings.

Make sure you have a wander into Osmond's Gill, it's a smart place, even without the little stone circle and the rock art.