Yep, I'm an idiot. Not sure how I got it confused but I'd noted down the day my extension of stay expired as tomorrow. Turns out it's today and it's now too late to go to Chaeng Watthana.

If I go tomorrow will I still get the extension (plus fine) or will it be refused?

Would I be better just flying out and coming back on a 30 day entry as I know I can extend that by 30 days. I plan to go back to my home country in 6 weeks anyway.

They will do the extension after you pay the 500 baht overstay fine.

You don't have to wait until the last day to do your extension. You could of done it a couple of weeks early and lost no days because the extension starts at the end of your current permit to stay.

Thanks Joe. Do you know if they will process the overstay fine and the extension in the same place at the same time?

They will do the overstay and extension at the same place.

Yep, as Joe advised they just gave me a 1 day overstay stamp plus all the forms to sign and a 500 baht fine at the extension desk.

Other than that I got the full 90 day extension after reading a few sentences to the officer out of a kids book I took with me. Fridays seem a lot more relaxed when they aren't in uniforms. One slight delay was caused by the fact that when I initially arrived it was in July, the entry stamp was correct but the stamp saying the visa was used was incorrect, stating the month as June not July. The lady noticed this and they messed about with it for ages, eventually ending with it being changed but it took them about 20 minutes extra just due to that small error.

I arrived at 7am and there were still 6 people ahead of me. By 8am The queue had snaked all the way round and was starting to spiral round again.

Just to mention-

Got the final extension for my ED the other day.

Chiang Rai seems like a VERY relaxed place for doing this,

AND the very first thing they have done each time is to check what school I am with, so that seems crucial.

My sense is that some schools either are not all that trusted, or...

there is a possibility that some schools pay some sort of "thank you" fee?

Not saying that is so, just wondering....