How do I bathroom / kitchen / extension? etc.

What Aggi said, we’re having to install a fire door between the kitchen diner (“kitchen”) and the stairs. Currently there is a hallway off the kitchen with the stairs coming down alongside to the far end. We need to fire door from the kitchen to the hallway to isolate the stairs from the kitchen. I’d have thought making the kitchen larger by incorporating the dining room into a single room would pass provided the stairs were behind a door.