Hi Byron,
I have had great service from the Southwark council people who, a couple of years ago, sent me details of the location within Camberwell Old Cem of an ancestor's grave, including a map of the entire cemetery and a detailed one of the section showing all the numbered plots. They were also able to advise me that the grave was in a "conservation area" (although I thought this meant it was being "conserved", it really means that the graves are allowed to rot while the bush grows over and around everything!!) They couldn't say whether any monument was still standing.
At the time, I was staying in London for a few months and was able to go down to the Cem and check it out for myself. Found the plot, cleared the brambles and bushes, and with two of my cousins we lifted the stone and took pictures.
I recommend contacting the Council and getting as much info as you can about the location of the grave - then Rootschatters can determine whether or not it will be possible to go and have a look for it.
Cheers
Prue