Larry's dead right one this one. My old man (Allan Jefferies) couldn't stand the man; I can picture him now moaning on about Joe Ehrlich and his DKW/MZ, and he certainly had a few run ins with him when dad was on the competitions committee of the ACU.
Incidentally my dad was in Germany as a Captain in REME,in 1945, and after helping to sanitise Belsen Camp,( another story, another day)he ventured to the Mercedes and DKW factory, and could have brought back one of the pre war race bikes if he had wanted. Well that's how the BSA Bantam started life anyway, with someone nicking the drawings of the equivalent DKW.After the horrors of Belsen, he really enjoyed himself in Germany, and he certainly should have written a book on some of the hilarious pranks they often got up to.