One of my friends is working for the German TÜV. When I ordered my MOG (in Britain) I ask him about problems with the COC and the German registration.
With a look at the official paperwork it looks like MORGAN has numbered the maximum sizes. So there is a very big difference between a small body small wheel Plus4 and a big wheel bodied Plus4 (which looks like this is numbered in the COC).
Greets René