I want to remove my existing concrete lintel above the fireplace and 'open it up' a little. I would like to replace it with an oak lintel accross the chimney brest. I would also like to install a solid fuel burner (stove) instead of having an open fireplace. Are there regulations as to the size of the lintel and the distance above the burner it will need to be installed i.e. the gap between the base of the oak lintel and the top of the stove.