What documents are required for a NON-O Visa when applying from the UK to convert to a retirement visa in Thailand?

To apply for a NON-O Visa from the UK and later convert it into a retirement visa while in Thailand, the main document required is proof of funds. Unlike the NON-OA Visa, the NON-O Visa does not require a criminal background check or health insurance. While some advice suggests needing three months of bank statements, this is dependent on the specific embassy's requirements. Typically, a closing balance of £18,000 is necessary, and applicants should submit a full PDF of their bank statements rather than screenshots. After arriving in Thailand, individuals must then deposit 800,000 THB in a local bank and hold it for two months for the subsequent extension application.