Get hold of eis on here they will recommend Axa Thailand. Don’t do Axa in the U.K. as they are expensive plus they have a huge excess. I’m a financial adviser and I’ve gone with Axa Thailand
Contact eis on here expat insurance scanners they use most companies I used Axa but use the Thai one not the U.K. one.
As for flights there are certain airlines allowed into Thailand BA isn’t one of them, Thai airways are cheap at the moment they only fly once a week on a Sunday and it’s direct at 11hrs 25mins
Axa is actually a french company but they do have offices everywhere. My one is the same as yours and everyone else’s will be also as that’s how they look, I’m a financial adviser. So they’re talking crap honestly
I’ve also just checked the U.K. Thai embassy and no such thing in there