In my experience living in Phuket for a few years, you just need a small bike and most licence allows this but I do not know the UK system. With Canadian licence, I managed to get an international permit that let me drive smaller bikes, and once you have the international licence, it is pretty easy to get a Thai licence.
I would not get into cars. Get a bike and use bolt only when you need a car. There is so much traffic most of the year that it is not fun to drive a car. Might as well get a bolt and keep working while you are in the car or doing other things.
Anonymous participant 983 overthinking is good when you deal with bureaucracy. He is right to ask those questions. Some country would scrutinize more but based on my experience applying for visa in Thailand and what I have read so far, I would apply and not worry about this for now.