Hi my neighbor is building a conservatory at the back of a terraced house(1928). We both have a single bay at the back and share a common tiled slanted roof above our bay. His intention is to remove the bay roof and I think the structure of the bay. The conservatory roof will run above the height of the previous bay roof. He is also building on a boundary wall between our houses. I am wondering if he needs permission for this? He has told me he doesn't need planning permission.