@Darren ********
usually there are two types of "term deposit" accounts you can have at a thai bank. One is where you tie up the money for a specific period of time BUT you can access it if you need to (even though you'd lose interest and get a penalty). <- That account is FINE to use for proof of funds for extensions
Another type is where you tie up the money for a specific period of time BUT you can't access the money until the term of the deposit is done. <- That account is NOT fine to use and immigrations won't accept it.