We currently have the ubiquitous Valour Homeflame Super in our living room, which is just mounted into an existing chimney. I want to update it with a more modern gas fire.
It's a 1930s house, with a fairly chunky external chimney stack running up the outside wall. There is a blanked off fireplace in the bedroom above, too.
I've been told by a non-expert that modern regs will force us to get the chimney lined when we fit a new gas fire. Have looked online and can't find the definitive answer to this. Some references to flu diameter and temperature but nothing definitive.
Anyone in the trade or done similar?