I have a vague recollection that if you have transferred to a particular recipient on 3 occasions then from then on you don't need an authorization code. Is this correct?

 

If this is not the case, does anyone know how to get around the inability to receive an SMS and make a payment when outside of Thailand?

I am pretty sure you are right about the transfers, the only account I have transferred to in the past few years has been my own K-Bank account but I never had to input an OTP from SCB for this.

 

Why can't you receive the SMS anyway? I haven't found any country in many years where my AIS phone doesn't work (and it costs nothing to receive an SMS).