My tupenneth is from experience in France ..I had/have a 650 Katana I built from spares but it was now in the way , here in UK. So took to my gaff in France..Issue being for the Insurance to be valid it needs and MOT and tax.. but its in France and there is no MOT on bikes not that would be accepted in Uk anyway ..
Some French companies would insure the bike on UK plates but its a temporary in theory policy which is valid 1 year but technically the bike could only be there 90 days ..on UK plates
I overcame the issue
However partly to see how the process works and to aide writing an article for the Katana owners club I put it on French plates ...What a nonsense, it had to be standarrd and inspected by local Suzuki dealer who hadn't a clue as to what it was, a letter from Suzuki Paris needed to be obtained first then inspected in line with the form..sent away to be stamped , returned to obtain temporary Carte Gris (V5) which would then get a full Carte gfis to my address in France but had to be signed for by me as its a legal document , but I may be at the address so it would have gone back to Paris and the bike not unregistered anywhere as part of the process obviously deregs from Swansea.
I did it , it took 14 months.. as opposed to a few weeks here in UK.
Downside although I have abike there , as said in France continuos registration is the law and unlike here you don't just let the policy lapse and get a new one , the new company inform the old company to take over the policy , so compare and drive down the fee ain't a thing.
Also draining the carbs and disconnecting the battery ensures instant starting and running , but it's a hassle when it's only for a week or so.
Now the bike is 40 years on course I could go historic and the lack of MOT and tax would make it easier to use my classic insurance , but legally only for 30 days..
But I'd have to rereg it in UK
Buying a local bike would've been an option , but again not 100% legal as the resident on the policy isn't a resident.