My apologies for being a bit tardy with this note.
Thank you to those of you who responded to my query a short while ago about the Edmonton Cemetery in London.
I had asked if "K5" referred to a specific plot or a section and a row number. Turns out it's just a section and row number (this information came >from an individual who is familiar with the cemetery, and who kindly visited "K5" to take a photo of one of the graves there for me).