I want to buy a second hand rear projection tv, around in 100 pounds is available in the market locally in london from private sellers i am worried about the lamp life, because its expensive to purchase kindly suggest what to look for when buying one of these tv's. also please tell me how to find hours life left in the lamp bulbs thanks bye

An original lamp (original brand name of the tv) can be "alive" there for some years. if you want to buy a tv an suspect that the one is good or not just turn around that area one or a couple of weeks if still working with a great bright and crispy color is good symptom> (some re-manufacture lamps just work a couple of hours even new)
The lamp's life is a question mark in this technology (optimistic ingeniers (brands) count these hours as 1, 2 ,3, (thousand hours) (actually some manufactures count the time ""it is a simple timer the microprocessor can manage pretty well, but is not the mean of a good o bad lamp""
but i recommend my customers to have a spare lamp (just in case you are watching a beatles show) and blowns, you have it in the garage and (consulting the user manual) you change it a as regular bulb in your house.
But the lamp life "and this is the tip": (only two states)

1. the picture tends to look dark or dimm (is logical because the high intensity the lamp works tends to create a tiny black surface on the heater and tends to consume more current and the answer is a dark picture as i told you already.
2. the lamp blown (of course the tv cannot work and the LED "lamp" turns on or keep steady on the front panel with a complete dark screen.