All I did was send one copy of my last bank balance statement. They want to see financial security for the 3 months length of the visa. That was 4 months ago from UK for a non o visa. OA. or OB will be different
For the last 2 or 3 years I have spent 8 months a year in Thailand. 2 X visa exempt for 90 days each and 2 x 30 days visa exempt. In all the years I have spent in Thailand, I have never done a border run. I have always returned home to the UK. Whether I have just been lucky not to get refused admittion or not I don't know. They are clamping down on border runs. I believe that returning home every time has saved me. I can't speak for others , this is just my situation
other way around. SCB for bills. Kasikorn will be my main bank for immigration. I know I will get the statement letter from Kasikorn for immigration requirements