Sorry if this is a dim question...In a few weeks time we are having our stair case moved to another part of the house to create a large kitchen diner with new bifold doors and a small utility room with downstairs toilet. We have a large building company installing the bifold doors, a specialist joinery company making the new stairs and a local builder doing the making good and plumbing. What, if anything, do I need to do about building regulations? Is it the responsibility of each individual trades person or should I submit a building notice application for the whole project?