Most condenser enlargers have that 'lethal' voltage running the lamp so that is not a concern (as you know from your 370 B&W) "Cold Lights" of course, can run at voltages much higher than 240V. You will need to put a new socket in place (pins on the high voltage lamps are slightly different) and at that time you can re-wire it with the appropriate voltage wiring and connectors.
Sorry but I think your advice to a person new to this forum and of unknown experience is irresponsible. A darkroom is not the place for dodgy, jury-rigged electrical gear no matter what voltage it runs on. OzJohn