What advice do you have for applying for a Non O-A visa in London for retirement purposes?

I did mine at London too , about 3 years ago , you’ll need a police record check , health check ( download form from the thai embassy web site ) . Uk bank statements . And I never actually got round to using it ( left uk ) until about 5 months after issue , note I also nearly got just under 2 years on that before I had to do my first extension ( 800k bht in thai bank etc ) .. note .. all the items you need as previously mentioned need to be ‘ bundled and sealed ‘ by a solicitor.

The Visa is only valid for 3 months. this means you have 3 months to enter Thailand and use this Visa. If you are not sure when you fly in April I suggest you wait till you sure about the departure date.