I need to enlarge my fireplace opening because I want to install a fire burning insert. My opening is about 3" short on the height. The place where I want to buy the insert claims I cannot open it because of the steel angle iron supporting all the brick work. They claim if I remove the angle iron, the bricks will crumble. I thought it was possible to remove the angle iron, cut the brick and reinstall it.

Does anyone have any experience to say otherwise?