Hi, can 240 light fittings be converted to use 12v power.

Generally we wouldn’t advise adapting the electrics on fittings as this may affect any warranties and safety certification.   This is also a very broad question as light fittings vary enormously.  However on some it may be possible to convert them from 240v to 12v provided that you also change the lamp holder (ie; the bit that a ‘bulb’ fits in to.)  We would stress again though that we wouldn’t advise it.