Hi guys, thanks for the info.
I did end up keeping the medal, mainly because I forgot to return it before the window of opportunity closed.
I'm pretty sure this is a post war Frankenstein/fake.
Most likely scenario, in my opinion, is that the frame is a leftover from the era and the core was stamped out of two mis-matched, worn out dies. The obverse die just being plain worn out. I think the reverse die was cracked but they continued to use it, resulting in the misaligned, chopped up 1813. The ring requires no comment.
Either way it's an interesting piece, I don't mind owning it. It's taught me a fair bit in the quest to authenticate or disprove it. The bigger lesson though, is to look before I leap, ha ha ha.
As this was never awarded to a member of the Wehrmacht, I have decided to award it to myself as a cross of foolishness. It will hopefully, in future, remind me not to ignore red flags.