I went in person last month to the DLT in Bangkok with a medical cert, cert of residence, passport and relevant copies, driving licence and IPD. I got the medical cert at a random clinic in the street. It was basically a blood pressure test. (I needed my passport at the clinic.)
(The DLT pushed the IDP back accross the desk. Didn’t look at it or make a copy)
The DLT gave me a link to the website below which was 5 videos and some questions and an appointment to come back in two days. The completed questions gave me a QR code to present on my return.
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Second visit I presented the barcode. Took a series of easy physical tests and walked out with my Thai licence within an hour.
Edit. I had downloaded an app called DLT smart queue to make an appointment. It didn’t work for me in Bangkok which is why I went in person.