No, you don't, if you have to ask. For the LTR Visa, you need to go through a rigorous pre-approval process, first. Don't just apply for it on the E-Visa system - you risk losing all that money.
Tried to tell him that already - only in different words. There is a reason this questions occasionally comes up - but people end up quickly forgetting about their smart vehicle import / export ideas in 99% of cases.
Sure thing. Just me general thoughts on it from hearsay - and why people usually refrain from importing
/ exporting bikes between Thailand and their home countries. But to be honest, I don’t know the details with regards to the UK. So maybe worth digging deeper.
Next to the shipping costs, you would have to pay import duties + import taxes on it. Which would already make it a good bit pricier than in Thailnd. But your bigger (and also expensive) problem comes when trying to register the bike back home, then. It would need to get a pricy evaluation. At least those things applied when the UK was still part of the EU. No idea if things changed since then. Doubt it, cause most things changed from bad to worse.
Unfortunately, requiring signed copies of sensitive documents is a common thing in Thai bureaucracy. If if you hand it out, do it as the smart Thai people do: Use a pen and cross the copy of your document out with a diagonal line. Then sign on top of that line and write the exclusive reason of that copy on the bottom of that line. This way, that copy is way less likely to be misused.