All:
Just to inform you and to round this off:
Steve Gray proved to be very willing to help. He still has a couple of original Mk IV badges in his stock. I could get one for GBP 22 + postage. However, they are 'slightly imperfect' in terms of chrome as they have been stored fo 20 years. Coincidentally, Steve is scheduled to meet with Juergen Mohr next week. He offered on that occasion to check whether the (reproduced) Mohr Mk VI badges are the same as the original Mk IV ones. If they do, I could get one supplied out of Juergen Mohr's stock. Steve himself plans to have Mk IV badges reproduced, so, as a third option, I could get one of those, I am not sure about the timing of this reproduction exercise, though. I will now await the outcome of Steve's meeting with Mr. Mohr next week.
Juergen