Only just realised that I wound up at the Banshee Stone exactly one year after Ryaner's vist! Access is still a nightmare, maybe more difficult since some of the trees around the megalith have fallen but after speaking with the farmer who has the rock art in his garden at Spahill, I think he said it may be cleared up soon. I told him of my woes getting to it after he explained the rock art was found nearby but his voice was so low I could barely make out something about clearing the place around the tomb.
I also came across this bit of research and detective work about the tombs in Carlow: http://glasnost.itcarlow.ie/~feeleyjm/dolmens/carlow-dolmens.pdf
It's fairly well overgrown at the moment!
http://img.photobucket.com/albums/v463/CianMcLiam/Carlow119d.jpg