German printing in Bristol

the original door to the Van Dyck Printing Works has it's engraved brass letterbox still in place.
I worked in this building, converted as the Wickham Theatre, Theatre Collection and Department of Drama at the University of Bristol.
It's was a very strong building built by German builders for large machines.
Correctly it is a letterplate, the box is behind, inside. It is now the access to the film and TV equipment stores,