I have no idea.
We have - living flame gas fire, good condition quite modern, can be sold seperately.
But then we have a fire surround, rose wood effect but not real, its in good condition (i hate it but someone will love it i am sure!) its a B&Q type affair but the back bit, not sure what it is called (the insert of the surround, which the fire sits against is solid grey marble.
Is marble worth anything at all these days? - reclamation yard not interested, not surprisingly. How much do you think we should put it in the paper for? Or ebay? (not delivering!)