This is the website for Camberwell Old Cemetery http://www.southwark.gov.uk/info/200073/parks_and_open_space...
If you have no luck there you might try West Norwood Cemetery http://www.lambeth.gov.uk/cemetery/
Note that the online database lists re-used graves only.
I suggest emailing the cemetery rather than phoning, so they can look it up when they are not busy. When you find the graves, you might like to create online memorials for them on Findagrave. You would then be able to request photographs of the grave sites.