@Paul ********
Your stamp shows, you entered on a 90-days Non-Imm-O visa, and got stamped in for a 90-days stay permit. Your visa is expired. You are inside Thailand on a stay permit. As soon as there are 30 days left of your 90-days stay permit, you can apply for the "1-year extension of the stay permit based on retirement", Which is NOT (!) a "visa". You said you already got the 800,000 in your Thai bank account, so everything would be perfectly pre-arranged, you can prove the money was in the account 2 months prior to your application with the "bank letter of guarantee" from your Thai bank. You do not need a rental contract or a health insurance to apply for the 1-year extension out of a Non-Imm-O visa, however you must be properly TM30 registered at your accomodation, if you want any service done by the Immigration office