Where can I easily apply for a new 60-day SETV in Thailand without carrying 20k THB?

hey everyone, i've got two weeks left on my 30-day extension of stay on my 60-day setv (uk passport) ... where is the easiest place to apply for a new 60-day setv? i'm on koh phangan at the moment but don't mind where i travel to (or how. flying is ok) as long as it's a super easy process. my priority is not having to carry 20k thb cash with me! tia :-)