1.) Get another Non–O E–Visa (Retirement over 50 years) from the Thai Embassy in London
2.) Do you already have the 800,000.- Thai Baht already in your Thai Bank Account??
if not, then have 800k Baht in your Thai Bank Account, so that on your next Entry months from now into Thailand on that new Non–O E–Visa you got from London, you can go to your local Thai Immigration Office to apply for an Extension of Stay with the 800k already 'seasoned' over 2 months while while you are away, outside of Thailand
3.) wanted to ask other Group Members: what are the Pro's + Con's of going from a Non–O E–Visa to Retirement Extension of Stay vs.
making Entry on free Visa Exempt, converting to Non–O in-country, then to Retirement Extension ???
if anyone has an ink stamp Extension of Stay from their local Thai Immigration Office, then that Extension ink stamp is transferrable to a New Passport
but, generally the LTR Visa Office (BOI) has an infographic about the 3 types of Thai Visas one may have in their passport