I am doing exactly that, I’ve decided against the 12 month extension and will border bounce into Vietnam, Hopefully IMO doesn’t give me any problems but I will be going with my Thai girlfriend. Hopefully, this helps?
I recently applied for this visa online from the London Embassy and yes you do have to show them proof of your finances. I uploaded recent bank statements showing that the funds are available. If you need help just PM and I can go through the application with you
Personally I would go on the flight and stay in Cambodia for a few days. Explore a beautiful country. Come back in and get a further 60 days. All depends on what you are looking for.
I sent £200 to Krungthai bank and it has stated that the money won’t arrive till sometime today. I contacted wise and asked have they changed there policy on immediate transfers to Thailand and they wouldn’t give me a straight answer. Just told me that transfers can take up to 48hours.