James
From the little information that I have been able to piece together and from dated examples I have I would say from 1935-????, who knows when the last one was produced, probably early war time either 1940 or 41. I'd be interested in any information on production dates you may have in your archives as there is not much out there on them.
We do know that there are some early post war Eickhorn examples out there but I have not heard of any F Dula marked examples either post war or pre 1935 but who really knows?.
Gary
