How to plaster around hole in the wall gas fire?

[JohnW]

Our room sealed Element 4 Modore 75h gas fire was installed yesterday and we're planning to board & skim the fake chimney breast to finish it similar to the photo below.

The temperature from the front of the fire can get up to 200 degrees Celsius.

Can anyone suggest how best to finish the opening so it won't crack or discolour around the edges please?  

 

[Mr Punter]

I would have thought plasterboard and skim would be OK. Why did you rule it out?

 

BTW that is a VERY impressive range of back boxes on the left!

[JohnW]

Thanks @Mr Punter, we haven't ruled out board & skim, I'm just afraid the edges of the opening will crack & discolour and was wondering if there's a better way that I'm not aware of.

The back-boxes are due to my pet hate of extension cables and adapters!! We've had 2 adapters get fried in previous houses from being overloaded, so, better looking at them...