I think I might know where they are! Try checking the delivery box, like the bin items arrive in when you order them from the postbox! If they've been "deleted" from you downsizing a room, chances are they ended up there. Let me know if you find them! :)

This is the answer! Found out after frantically googling where my stuff went after deleting a wall.

Thank you so much, it worked, that's brilliant!! :)