Hi Conny, for your information:

There are no issues with Dutch registration paperwork in Western Europe, because the homologation
requirements are the same between the Netherlands and Germany.
I would suggest that you, or any other buyer go with the trailer, the Dutch registration and the bill
of sale to a Truck garage, which offer German technical Tuev acceptance.
These guys can provide a technical “full-acceptance” and they would give you, in case that the
trailer passed the test, a certificate for the motor-vehicle department to get a German title.
If you or anybody else needs an address in NRW, please contact me via PN. I could mediate a contact.

Greetings, Sven