I found the photo below (sorry it is sideways!) in my copy of "Motorcycle Apprentice" by Bill Cakebread (current title.....a good read about apprenticeship at AMC in the late 1950s). I have not seen this image before and there is no explanation of the machine in the book other than the caption which reads "A wartime development that might have been useful for the winter commuter". Was the ski attachment an AMC fitting or available generally and was it ever used on any bike operationally by the Allies?