Female married to Thai man you don't need the 400k in bank go to immigration they have a form with everything you need listed on it I'm going back at the end of the month just applied to go from retirement to marriage visa waiting on immigrations decision. But I went there before I applied they gave me a list of all the paperwork I needed
Bangkok bank will only do 6 months in branch have to apply for longer takes 7days. In branch its β150 for the 6 month printout and letter costs the same