We also appear to have a extra door.
Apparently John the joiner and Lee the builder had decided there was spare space on the landing. Why not build a cupboard. John decided to put a door in ready for it. We do agree, but think the space should be accessed from the landing, rather than, what is going to be, the study.
And this weekend I get to go mad with a marker pen. Sockets and light switch placements. Don't worry, I will be supervised by a responsible adult.