Well if you require facts then would best go to your chosen department of land and transport office and ask them, as we all know it can vary slightly from place to place.

All I can relate to you is the experience of a good friend that let his lapse by more than one year. So, where as your first time in obtaining a Thai car and/or motorbike licence you can use your existing licence from your home country, provided you have passed the relevant tests in that country, to bypass sitting the actual physical road test. But, and this was according to his local office! It can vary from office to office, that you cannot use that if you have let your Thai licence expire. By more than a year.

So, he had to do the actual road test on both the car and motorbike.

Actually think another friend in the 'Surin' province had to do the same as he had let his lapse as well!

You will more than likely have to sit the full test and driving ability.