A friend is having trouble with her boiler (very noisy and cuts out). She was told by a heating engineer she should replace the boiler. I noticed after a cursory glance that the noise was coming from the fan motor. I was quoted £524 for a new fan unit on a spares web site. Through a trade counter got a price of £145 for a fan assembly On ebay found a plumber who sells new bearing assembly kits with fitting instructions for £7 next day delivery. This lady is a pensioner and would probably have had to pay for a new boiler when a £7 kit taking 10 minutes to fit gets her boiler back on line. There should be laws against this sort of extortion.