In response to the claim that a UK driving licence is valid in Thailand: Not so – never has been. Only a Thai driving license specifically stating for a “car’, and not for a Thai motorcycle, is valid to drive a car here.
An international licence for a car is another “short term option” for holiday makers, but I am told that if that is more than one month old you may still have a problem … at the police officer’s discretion.
A UK driving licence has never been valid to use over here. The person that hires you the car in Thailand is not pursued for letting someone hire a vehicle without the proper documentation; that is why so many foreigners get stung. Thai police never pursue them for allowing the hire and you have no course for redress.
What is worse is that if you have an accident you will find that you had no valid insurance either because you did not have a valid car licence in the first place. Once that comes out, regardless of fault, you would have to pay. The reason: because you should not have been driving, and if you were not, then it would not have happened.