Personnally I don't think that the price you have been quoted is too bad. Make sure that the engineer powerflushes the existing pipe work, if this is not done well your newly fitted boiler warrenty could become invalid due to the debris and sludge left in the rads and pipe work. Make sure that the system is brought up to building regs part L energy efficiency. this will cost but it is required.
District 6 (St Neots)
May 2007