Got a dilemma, should i scrap the roof chimney (which is leaking) and with this the lounge gas fire which uses it, and just use the central heating? The boiler is an A grade Worcester combi single zone. So if i do use the heating all the house is warmed up, so that sounds inefficient, but on the other hand having a gas fire on with heat going up the chimney also sounds inefficient. What is the modern day thinking please?