The 'E' Type Forum

Hi all, my reversing light wasn’t working so I went to swap out the bulb and found to my surprise the bulb was a 380 twin filament, when I checked the lamp list on the forum it’s listed as a single filament 382 but the holder definitely only takes the 380 with off set lugs. The cable leaving the lamp fitting has a redundant red wire, any idea what the red wiring should connect to and what the second filament is meant to do?

Thanks