Good read.

NL/FE should be business as usual as they have blanket carnets.

But no-transport events like Spa/La Man are pretty much facked.

https://www.motorsportuk.org/movemen...s-post-brexit/

you pay something like £350 for the carnet and then another 250ish insurance against value of bike
You can avoid insurance if you pay the whole value of the bike into a holding account that’s then refunded to you when you take it back out of the eu to Uk