Hi
I bought a used Thruxton, not through a dealer, he'd had it custom painted before he picked it up from the dealer but the registration document still had it as the original colour, don't ask me why. I queried this when I bought it and he said he'd never realised as he'd not had to have the vehicle MOT'd, he showed me all the docs and receipts showing where and when it had been done, anyway I was able to put it right on the reg doc by informing the DVLA, so not sure if you have the same reg process in Croatia