London Road Cemetery, Mitcham, CR4 3LA (Google map).
In the Commonwealth War Graves section, plot 14, of this cemetery there are three gravestones for Auxiliary Firemen who died at the Surrey Theatre, on 10th May 1941.
The Commonwealth War Graves Commission (CWGC) website doesn’t include the details of these graves in their list of the war graves at this cemetery, because, as commented below, they are not classed as full war graves. The three gravestones in plot 14 are shown below, the sequence being from left to right as viewed from the path, which leads from the entrance in Victoria Road.
E. G. Pepper, aged 32
E.F. Robinson, aged 35
C.A. Elliman, aged 37
A pdf plan of the the layout of this cemetery is available from Merton council’s website.
A plaque near Blackfriars Bridge reads
In memory of 11 London Auxiliary Firemen, a Sub officer of the London Fire Brigade and five Mitcham Auxiliary Firemen, killed by enemy action while relaying water from the basement of the demolished Surrey Theatre, which stood on this site and was then used as an emergency water supply, to fires at the Elephant and Castle on the night of 10th/11th of May 1941
The five firemen from Mitcham are listed below. The links are to Commonwealth War Grave Commission web page entries.
Source of age and address is the Commonwealth War Grave Commission website.
Probate for Edward George Pepper
PEPPER Edward George of 1 Aberdeen-terrace Merton London SW19 who is believed to have been killed through war operations on 12 May 1941 and whose dead body was found on 12 May 1941 at Surrey Theatre Blackfriars-road Surrey
Administration Llandudno 4 July to Kathleen Isabel Pepper widow. Effects £329 14s. 10d.