I'm going to install a gas fire in the next couple of weeks. The
existing fireplace is quite large and I need to fit some kind of board
over it, leaving a cavity just large enough to mount the fire. What is
the best material to use for this and who sells it?

Years ago whilst assisting my dad in doing a similar job, we used a
rigid, mineral (non asbestos) composite board that was resistant to high
temperatures. I can't recall where this came from. Any pointers?


Best regards, Jim