I have been visiting this site for over 15 years. 5 years ago I could see that they had noticeably worn since my first visit. Sadly last month (Aug 2019) they were barely visible any more – see photos. The sun symbol and the cross (plus shape) symbol have pretty much vanished. The walls still look reasonable when photographed in landscape panorama but close up the individual cups and rings are extremely faint. So get here quick before they vanish completely.
To assist your visit do not follow the path from the gate diagonally across the field and over the wee bridge then right up through the tricky brush, fallen trees and steep muddy slopes as per the old directions. Just park as described and go through the field gate then head straight across the field to the piece of fence/stile on the other side sprayed yellow. There is a photo of this stile/fence among the photos – dated 2007. Climb over it and cross the small muddy burn and the walls are straight across from you up a slight rise. Much, much easier than the other way but wear boots or wellies anyway.