I just heard back from Old Calton cemetery, they did have a section called John Muir's ground, but it was moved to make room for the Waterloo road around 1830. Their record keeping started in 1805, he said if she is there she would have been moved to the New Calton. The gentlemen helping asked for the clip from Scotlandspeople and he will confirm a few things; like whether or not she was in that area or if she was in the regular SWC. If she was in the regular SWC corner all graves in that area was moved and not marked; which is sad if those graves did have someone looking for them they would be no way to know who was who. I'm hoping for the first and that it was marked.
I will update, when he gets back to me.
Thank again all
Mel