as an experiment, I didn't leave the house without my passport for three months in Chiang Mai, either in my pocket or hill tribe bag, everywhere I went, even out getting absolutely smashed. I never lost nor damaged jt.
an international driving permit, yes. If you have a full UK car license the RAC usually endorse the bike stamp on the IDP. As far as Thai authorities are concerned, the average UK car license appears to have bikes also, it's how I got my Thai bike license.
good luck with what? I showed my UK license to the transport office in Chiang Mai and they gave me full car and bike licenses. I have a full license in Thailand. But for years before I used to IDP with the bike endorsement and my UK car license, it was fine.
And final thing, no, the authorities are NOT smarter than most people give credit, insurance companies are a different thing, they will find any excuse not to pay out
please read what i just said. The RAC always stamp the bike endorsement on the IDP, the UK car license appears to the Thai authorities to allow bike riding. To the extent they will even transfer it to a Thai bike license.
You do not need a UK bike license to ride in Thailand