This is going to sound like (another) ill-researched question.
Daughter's lounge has something like 24 small bulbs in the ceiling arranged in 2 banks of 12, each bank being fed via half of a dual dimmer switch by the door. One bulb has gone, but her husband hasn't been able to get it out from the mount so doesn't know whether it is mains or low voltage. I have always avoided these lights since early days with something that looked like this and melted the transformers above each bulb. I've looked at pictures on the net and seen that bulbs like this are called GU10, MR16, MR11 etc. Can one measure diameter or something to find out what they are?
The problem is that when they switch on in the morning in winter, the lights don't come on. If they leave the dimmer knobs turned up, first one bank will splutter into life after a few minutes, then the second. Daughter thinks this is definitely temperature related, as the lights work normally in summer.
Is this likely to be just a matter of a dually-faulty dimmer switch or is there likely to be some other possibility. Are these most likely to be mains lamps or is there a possibility of there being 12-volt transformers after the dimmers.
Thanks for any illumination!