Check out the title of the thread...
The destination part is admittedly obvious. But Simon's eHam login is HS0ZIB, so my guess is that he's looking for reciprocal privileges in KSA for a native licensee from
There are probably about 200 or so independent licensing authorities, so there are about 200*200 possible situations. Only a few of the relationships are covered by collective agreements (CEPT, IARP); everything else is based on either individual one-on-one country agreements or treaties, or standing rules (in the destination country) for visitors. Neither Thailand nor KSA is a party to CEPT or IARP. I can't tell if there is any sort of one-on-one reciprocal arrangement between them.