> Perhaps if the OP searches the photos on Geograph around Lix Toll? I've car camped near there several times in the past but don't recognize the rock. If it was further afield I'd suggest the Popping Stone near Gilsland (a well known romantic spot in olden days) but the rock there is sandstone.
I think it's Craigmaddie, too. Somewhere in this region I have seen similar places.