...thank you so much...I hadn't even consider the under consideration issues so just leaving and start again from UK as per my original idea sounds best.
non o 90:day retirement....exactly as immigration in Udon Thani advised was what is needed. Plus passport,obviously, tenancy agreement and even residents certificate letter from immigration office. I don't doubt you have knowledge and keep up, but factually,your statement that it is not a problem to open an account if all is in order is wrong. I just wanted the person you are advising to know that. No insult intended.
I'm sorry but that simply is not true in every city and every bank.
I took absolutely everything necessary to the three big banks in udon Thani a month ago, Bangkok Bank,SCB and krasokorn all refused.
Krungsri opened an account for me with exact same paper that I took to the other three banks. So whilst for you it may have been simple it's not the case now, certainly not where I am. If it is simple with the right paperwork etc then all three banks that refuse would have opened an account for me and not just the fourth bank I tried.
Sorry have no first experience but I do know someone whose wife died and his visa was not renewed as he was technically not married any more. Seems very harsh. Maybe just do retirement visa.