Hello New to this and just looking at another thread and saw your comment. As a building surveyor and building services engineer I am sorry to say that its 99.999% certain that this fault has nothing to do with your wiring or supply because lamps (bulbs) have a life which is very much dependent on two things, the operating voltage and the temperature of the lamp. If your voltage was incorrect it would quickly be discovered by the utility board and in any event you would start having problems elsewhere and not just a few lamps, so would neighbours. Lamps blowing regularly is usually caused by cheap lamps or lamps in situations where they get too hot which dramatically shortens the life of the lamp. This is true of both incandescent lamps and the new compact fittings. If you had a wiring fault a circuit breaker would trip and would not blow the lamp. Your Electricity Board by law must deliver 230 volts +10% - 6% (ie. between 216.2 volts and 253 volts), so if you have an accurate meter and if you are careful you could check this. Remember that if for example your voltage is always on the high side, mine is 249 volts at present, this will shorten the life of lamps but it's still within permitted tolerances. The ten year NHBC guarantee covers building faults usually of a serious nature like structural defects. I regret that the NHBC will not entertain claims for blown lamps which is obvious could not be as a result of a wiring defect. I note that you state that you purchased the house ten years ago from the previous owners who I assume were the first owners. As the guarantee is ten years total and would have commenced at the time of the original purchase by the first owner it will have long ago run out. Sorry but I hope this helps.