Hi, I attempted to open up my fireplace but the chimney failed the smoke test. I have a cast iron surround I want to fit as purely decorative and leave an open hole where the insert would be. Should I get the chimney breast plastered before or after attaching the fire surround? It's only a small area to plaster - where I took the plaster off to check for a lintel - how much is a plasterer likely to charge? Thanks for any advice, Polly