If you check in the transformer box for the light , you may find there are different voltage tappings on the transformer, so you may be able to change the voltage to one which you can get an LED bulb for. , search for xx volt BC led lamp. This came up before on one of the forums I frequent, and I found some LED BC lamps which were for canal boats, so they can be bought! You could make one out of an old BC bulb cap with an led lamp soldered into it, or also you can get adapters for BC-SBC and BC to ES or SES
Phil
Edited By Phil Whitley on 20/09/2020 16:46:44