I live on the top floor of a Georgian converted townhouse. Currently I have a really old ( open vented? ) Stelrad regular boiler from decades ago that allegedly flues directly out into the kitchen chimney stack. Boiler works but it's on its way out and will probably be condemned at some point. Various heating engineers have taken a look at a solution but I seem to be stuck between new safety regulations that don't allow the flue into the chimney stack, and listed building regulations not allowing me to install a vertical flue that vent's through the roof or anywhere noticeable. Luckily as I'm on the top floor, an inside the chimney flue may work as the distances would be relatively short. I've only seen solutions for floor standing boilers with chimney vents options. As I'm in a 1 bed flat, that would be too large and a small wall mounted regular ( or even combi ) solution with this type of vent would be ideal. I wondered if anyone has come across a similar situation or has any advice to offer?