UK Trailer registration
This may have been posted before but here goes anyway.
Anyone contemplating driving in the EU in a UK regged vehicle and towing a trailer is advised to read this
Yes for non commercial trailers under 3500kg registration is voluntary but it might still come in handy to fend off over an zealous 'flic'.
Note that although the coming into force of the Vienna Convention was timed for the March 29th. exit from the EU the fact that it was brought into force means that it continues to apply from that date.
Trailer of course means anything towed behind a vehicle.