Martin Howarth - Glad to hear about the London BB routing connection. Readers should note that this is not a 'Wire' or Swift code funds transfer. In America it is considered a 'domestic' transfer using the ACH Automated Clearing House process. BB New York is a Thai Bank of course but also a U.S. Federally Chartered Bank.
You cannot open a personal account at Babgkok Bank New York. BBNY is a Commercial Bank only. BBNY does provide routing from other American Banks to Bangkok Bank Accounts inside Thailand.
The Non Immigrant O visa for one year - the one that required exiting and reentering Thailand every 90 days - for people age 50 and over for a type of 'retirement' was discontinued some time in 2016 - perhaps late 2015. I had one in 2014.
About 4 years ago - (before that time and a bit after) Thai Embassy / Consulates would issue a One Year Non Immigrant O Visa just for being age 50 and over (no other reason). It required an exit every 90 days and reentry into Thailand to get another 90 days. I had this visa in 2014. This type of O visa stopped being issued sometime in 2016 or so. It is still issued in this manner for marriage, volunteering and other special reasons - but not for just being age 50 or over ('retirement').
The Non Immigrant O Visa based on being age 50 or over (intended for 'retirement') is Single Entry 90 days. Which can be obtained at a Thai Embassy / Consulate in one's home country, or in a neighbor country to Thailand and even at Thai Immigration offices. This 3 month visa can then Extended for One Year at a Thai Immigration Office in the last 45 - sometimes last 30 days by applying with form TM.7 Application for Extension - fee 1900 baht.
You will be successful in coming and going in and out of Thailand by going to your home country - one time - and getting a Thailand Multiple Entry Tourist Visa - METV. This METV is good for 6 months of multiple 60 days stays. Timed correctly you can get almost 9 months out of it. You can exit and reenter as many times as you want within the 6 months.
Check the website of the Thai Embassy in your home country about application requirements.
I think the Embassy website info is out of date in some ways... About 4 years ago -(before that and a bit after) Thai Consulates would issue a one year Non Imm O Visa just for being age 50 and over (no other reason). It required an exit every 90 days and reentry into Thailand to get another 90 days. I had this visa in 2014. This type of O visa stopped being issued sometime in 2016 or so. It is still issued in this manner for marriage, volunteering and other special reasons - but not for just being age 50 or over.