I must admit I don't know much about the oa, as I applied for the o, but I thought it was a 12 month visa and if you time the insurance correctly and leave Thailand just before the end of 12 months, you get approximately 24 months, without needing to extend?
If that is the case, for someone planning to travel around, it might be preferable to depositing the 800,000 for the non o.
I think the obvious options are non o or oa retirement visas.
The non oa requires specific insurance and criminal checks etc.
THE non O requires you to deposit 800,000 baht in Thailand.
If you get the non O apply in the UK and then open a bank account, deposit 800,000, then once the money has been in the bank for 2 months extend your stay by 12 months and get a multiple re-entry permit at immigration. You can then extend every year.
yes that would be a pain. They are just being awkward, they can provide the papers easily for you, as I said when I moved from Hua Hin to Sriracha I asked them to transfer my account and they said they couldn't, so I asked them for the documents for immigration and they gave me them immediately, so it's definitely possible, but TiT.