I've googled for this but found nothing that really relates to the problem, though it's hard to form a search which doesn't produce references to 50Hz flickering or to use of dimmers, neither of which is my problem. So if this is an FAQ please point me to it ...
I had my bathroom/adjacent toilet completely "done" last August. The bathroom has five LV 50w halogen down-lighters in it, the toilet another three. The house wiring was done about a year before.
All was well for quite a while then one of the lights in the bathroom started to act up. It started by fading and brightening for a fraction of a second, then for seconds at a time, and over a period of two or three weeks (while we had calls in to the team that did the fitting) it went to being out for minutes at a time and then finally dead. It's not the bulb because it works OK in another fitting.
Then about a week ago another one of the five in the bathroom started with the same performance; it's got somewhat worse by now, and today one of the ones in the separate toilet joined in. (And we're starting to write breach-of-contract letters ...)
Can someone suggest what's causing this? I have a reasonable knowledge of electronics and what not, and can't imagine what's going on. When they finally do pitch up, how much of it are they going to have to have access to? I've insulated the loft since the job was done.