So the lovely carved stone with the pattern, this picture
http://www.themodernantiquarian.com/post/57470/bryn_celli_ddu.html
looks like it was found in the ground.
So now (a copy of) it's perched outside the front entrance of the tomb. But I should assume it was never there at all? And maybe wasn't supposed to be seen, even (like the hand prints on the pool farm cist)? Or was it standing up somewhere and then fell over in the dim mists of time? I've not really thought about it before. Does anyone here know its story of discovery / interpretation offhand?