Wow, finally............
I have stared at this car for a month and I thought I had the answer immediately......
Must be a Horch 830 BL.
But then I realized the radiator surround was much more narrow than a Horch and had to start all over again.
My current opinion is that this is a Steyr, most likely a 430, from 1933-1935.
In spite of hours of investigation, I cannot come up with the coach builder but perhaps that is enough if correct.
Bill