I have found the graves at St Kilda cemetery can be hard to find as not all are numbered and for the ones that are, the number was engraved into the stone which had since been eroded by the weather which makes it very hard to find and read. For my family I have two numbered graves to get an idea of the numbering system in that section and simply counted up to the number of the grave I am trying to find and assume that the vacant bit of earth is the grave I am after or cheer silently when I find a headstone.
I'll send you a PM