Few days ago, I switched off the kitchen light at end of the evening, it went out with a bang, and the RCD in the consumer unit had cut-out as well - not a split-load unit. Switched RCD back on, all OK, except kitchen light not working - the tube is good, checked in another fitting. Would this have been the lamp ballast failing? I have not known this before. I have now replaced the unit with a LED bar, far better I reckon.