ah. . I see. Sorry, I'm easily confused. Lol. Old age I'm afraid. I'm going in again to Phuket on 60 exempt +30 extension. I was told I can apply for an O there to convert to retirement. I hope that's right.
so you already have the O visa. Not sure how you extend it if you're in UK, thought you had to go to immigration but one of the experts on here might know.
I don't think they issue visas at border. You'd apply on line for that and takes a few days. You'd be better to enter on the exempt of visa option if passport is from one of the countries on the list. You'd still get 60 days. No visa required and can extend 30 days too.