As to my knowledge it’s either get online METV whilst in UK or if you’re in a neighbouring country you’d have to get a visa via the embassy.
Which makes no sense, it should all be online it’s 2024.
Also what’s to say you can’t get granted a Thai visa but decide to visit neighbouring countries first then heading off to Thailand? Surely they wouldn’t expect someone to fly back to uk to catch a U.K. to Thailand flight just because that’s what the visa says?
So if you come on tourist visa exemption you can come as much as you want by air.
Only can extend 1 time per entry.
I recommend you to do what I’m going to do this month.
If you have £5000 in your bank and can get bank statement proof you can actually pay £150 for a 6 month validity METV (Multiple Entry Tourist Visa)
Which will enable you to stay for 60 days each time + 30 day extension, then you can leave and come back via land border to do another 60 day + 30 day extention.
You can do land border 2 times per calander year, since we’re in March and can visit for 3 months at a time on this visa you could actually do land border runs way into next year.