Shaun
I was under the impression that if one had a gas fire/back boiler the chimney had to be lined are you saying they need sweeping as a conventional coal/wood fire, that would make one of my wife family very happy as he is a sweep, also I did not know gas fires used coal, I thought it was coal effect non combustionale.
I will think any thing to do with GAS must not have a back draft.
I stand to be corrected as always.
Len