John, it should be the same in all EU countries. If the vehicle is in original (not modified) condition and more than 30 years old, there shouldn't be import duties and VAT will be 6% on the value. They're treated the same way as antique collectibles.
FROM the UK, TO EU is 3% import tax, IF it is a UK made vehicle, + VAT (from that EU country) on the invoice (must be reasonable and possible to “prove” so there must be a traceable name on the invoice for a bike older than 20/25 years..
Never heard and experienced “6%” of the VAT or like wise… for 30y old classics… at least not in the Netherlands..
And we do it for a living (regularly) BUT i might be wrong ;-)
Very important now: BEFORE export, you need to fill in ALL the proper export and import forms, BEFORE entering the EU!
I have seen that people were sent back on the ferry, with the bike, because they hadn’t the proper forms from the UK and EU..
Tbh not worth the hassle for a few quid to be safed upon