Alistair,
I believe that one of Aeromans cars ended up in Germany but this may have been through a dealer.
If it's anything like the issue with overseas cars coming to the UK I would image that leaving it UK registered may have its advantage in tax avoidance.
Would the matter of re-registration be down to the individual purchasing?
I had some interest from Germany when mine up for sale. I'll see if I can find the details and PM them to you as the guy just messed me about.