A number of brass plates were recovered from the scrap merchant after being stolen. They remain in the cleaner's office.
There seems to be no reason why they can't be put back in place. There aren't enough to do all the corridor doors. It has been proposed to use green perspex plates. Perhaps individual corridors could be done in consistent style.
14 Feb 2017 - Paul Sulsh agreed that there's no reason why the plates available (stored in Paul Joy's office) can't be put back.