Ian,

That article of Camerapedia is wrong in that it states the life of Mentor cameraworks to have come to an end by the end of the war.

But the small company lived on, designed new models, became a state enterprise in 1972 and finally was cancelled in 1980. However small scale production of Mentor cameras has gone through in the same workshop which now made part VEB Pentacon Dresden.
The Mentor range were the only GDR LF cameras.