smell coming from gas fire smells like rotting cabbage or egg

I would have thought that when the smell was investigated the fire was taken out to make sure, but if this hasn't been done than your thoughts may be correct and the rear of the fire needs to be checked but the smell you describe also comes from drains .

Hi, possibly giving you same info/advice as transco! Get a gas safe engineer round to service it, he will take apart,clean,inspect flue/chimney,any ventilation required smoke test, reassemble and test if any stuffs come down the chimney a roof/chimney inspection may be required,by ladder! Kieran