Propaganda Photo Of A WW2 Ambulance Driver

This staged photo used for propaganda purposes shows an ambulance driver about to set off to an incident. It's a well known photo but of interest is the extra insignia flash below the Ambulance shoulder title. I believe this to be the red cross on a white field symbol for the City of London (symbol has a sword in the upper left quadrant but this image doesn't show this).

Propaganda Photo Of An Ambulance Driver