Indeed, Dogle, the "Downwards Identification Light" description in my Hastings Pilots Notes reads:
"The three downward identification lights in the fuselage nose are controlled by a switch on the coaming panel. Red, green or amber can be selected and, by pushing up the small lever on the morsing switchbox, the selected lamp can be used for morsing"
So very much the "colours of the day" as well as discrete messages to/from ground parties.
A bit of a treat for us from Avialogs for us, Danny. A repro of a painting used by Vultee for publicity purposes:
Avialogs - Vultee aircraft
Tantalisingly it seems to show our elusive wing top wires going to the lower fin. Or does it? Have to admire the sanguine crew member having a last fag alongside a fully fuelled up, and currently being bombed up, Vengeance! Mk I or IV?