Go higher up and demand a different line manager if I were you. Unless your room really IS untidy! I have been told off for room untidiness before, but it was justified and tidying it up made me feel much better! If you have a vindictive streak, watch THEIR room and if your LM's room becomes untidy, report THEM to the Head! Know what you mean about 'somebody making me trip up at every opportunity.' Teaching feels like this sometimes!