Bought a micromarble fire surround and gas fire from a shop who organised the fitter but gave me option to choose my own. The fire surround was fitted and two days later when the gas fire was being fitted I noticed 2 flaws in face of material of fire surround and telephoned shop. The fitter was sent out to try to repair the marks but was unable to do so. The shop is now ordering me a new one and will have it installed but they want to charge me £100 and I'm not sure what for. Apparently I should have been invited to examine the item before fitting and the shop said the only supply but it is what they have supplied that has the marks. Should I have to pay?