Not Bangkok but did it in CM last year. Needed the address certified - free in CM immigration, 15 minutes for both licenses (need one for each license), needed another medical (sent away by license head for not having one), four photos and payment. Went on the day of expiry and was also told that anytime after would be ok but probably best not to leave it too long in case you get stopped with expired license, although I guess someone will say this is ok.

OP, a sliver gratitude often goes a long way.

Sorry a bit off topic but, does a Thai driver license is generally "accepted" in western countries? And does one need to apply for an international driver permit - if so where can you get that?

Thai driver license is NOT generally accepted by the western countries. You may apply for the international license here in Bangkok.

In the UK you can drive on your home countries licence for up to 1 year (3 years for EU countries). After that you need the appropriate UK licence.

Unlike Thailand, international driving permits are not required in the UK, but I would recommend getting one if you were planning to drive whilst there just to simplify matters if you got stopped by the police.

The IDP needs to be obtained in your home country.

My good lady has a lifetime Thai DL that was accepted firstly in Luxembourg and secondly in UK meaning she got a licence for those countries without taking any extra tests.

That was in the darkages tho, so it may be different now...I'm full of useless <deleted>

Closed topic. As mentioned, there is a pinned thread for this subject, in the Thai Motoring Forum.