What documents do I need to apply for a retirement visa in Thailand as a UK retiree married to a Thai citizen?

Why not get a non o based on marriage only 400k and less time sitting in bank

Paul, you can apply for either non O based on retirement or based on having a Thai wife. The retirement one requires double the funds the Thai wife does, 800k vs 400k but the retirement one requires less paperwork. I suggest you go to your local IO and get the requirements handout for both options and pick the one that suits you better. I easily qualify for the retirement option but I've always chosen to use the Thai wife option because that suits me better.

mate , a marriage visa is a bitch of a thing to get, sooo many hoops to jump through. If you can put 800,000 in your bank account or have at least 65,00 baht a month paid into your bank account, get the retirement visa soo much easier.

First off you didn't come here on a visa on arrival because there isn't one issued for your nationality. You showed up here without having bought a visa from a thai consulate before hand and were stamped in free for 60 days on what's called a 'visa exempt' entry <- it's not a visa on arrival, not a visa at all, just a free stamp entry

You and your wife need to go to your immigration office and get the hand out listing the requirements to get the initial 90 day Non-O visa based on marriage to a thai for 2000baht.

Most offices require you have a minimum of 15 days left on your current stamp to apply (because of the two week review period before you go back to get the Non-O visa and 90 day stamp inked in.

The whole process (simplified) is like this

1 - go apply for the 90 day Non-O visa for 2000baht

***wait the 2 weeks under review

2 - go back get the Non-O visa and new 90 day stamp inked in

***wait until you have 30 days or less left on that 90 day stamp

3 - go apply for the year extension for 1900baht get a 30 day under consideration stamp

***wait until that stamp runs out

4 - go back on that date to get the year extension inked in

5 - buy a re-entry permit if you are going to travel in/out the rest of the year

Obviously for the initial 90 day Non-O visa and the year extension you need copies, photos, bank book, bank letter, marriage documents, wife's documents etc <- that's why I said GO to your immigration office and get the hand out listing the requirements at that specific office

sorry this was long, I hope it was helpful