I got a yearly extension based on marriage last year. I used the 400K to buy a car a few months ago, I am now about to transfer 400K from the UK again for the next extension (2 months before I apply). Is this ok or will they check that the money has been in my account the whole year? Also I am doing it in a different Immigration office as I've moved, I read that this might be a problem.
TLDR : Answer Summary
To apply for a marriage extension in Thailand, the funds (400K THB) must be in your account for at least 2 full months prior to your application date. Transferring money from the UK recently is acceptable as long as it meets this timeframe. Additionally, since you've moved and are applying at a different immigration office, ensure you file a TM28 form for the change of address and inquire about any necessary TM30 documentation.