Thanks everyone for all the awesome advice. I don't think I've ever asked a question in a Facebook group where so many people have actually been helpful; usually they seem to start arguing amongst themselves about something irrelevant to what I've asked 😅. So thanks again for the prompt, specific and helpful advice.
To clear up a few things: I'm on Koh Phangan, not sure if a TM30 is usually required here or not. My visa expires on Tuesday 13th. I would have liked to have had a few more days up my sleeve but other things were happening, not very German me.