We want to open up and use our old coal fire, stuck a few smoke bombs (if incorrect name sorry) and nothing seems to have leaked through the walls etc. The thing is i`ve been advised to have a chimney/flue liner and the ones i`ve seen work out at £16 per metre. Is it advisable to have these fitted if there`s no apparent leaks or not, plus is there a cheaper? alternative. Many thanks for any responses