I've ripped out the 1950's tile fireplace and got a cast iron insert
fireplace. I've also got a fire surround.

When I put the fire surround to the wall there is 2.5 to 3 inch gap between
the wall and the inside face of the surround.

It looks as though I have to move the cast iron fireplace forward to suit.
This leaves a gap between the fireplace and the wall. How should I fill this
in?

Hope this makes sense.

mark