I have just bought a two bedroom 2nd floor flat that currently has a warm air heating sytem and hot water tank. I am going to strip them out and have a combi sytem installed. The only real location for the combi boiler is pretty much central in the flat where the current warm air heater is. The flue currently discharges through the pitched roof, and is where I expect the new flue will discharge. I can fit all the rads and pipework myself however just need somebody to connect the gas to the boiler and fit the flue through the roof, does anybody have a rough idea of how much this will cost??? I will also be supplying the boiler myself.