OK so no joy with the head light, my plea for some golden hens teeth, from other DKW Hummel owners, have found a mass of deaf ears.
So I went off to our local bike stripper, and found some "near size" head light systems.
So as these things now days all come from China, and are made of recycled plastic, I had to cut, change, re-fit, adapt, modify, extend, elongate, and just plane "make a plan"
Well the result is a nice fitting dim/bright with park head light, that will fool most, and will work till the real McCoy is found.
Got the magneto and the dynamo working today, so now we have spark, as well as lights.
With the new spark plug on the short shopping list, we will go forth into the spare part world, and locate a "interchangeable" plug to get her running.
having most, or all, (I hope) parts, we should have her running soon.
Will keep you informed.
Herman