From the UK-Thailand Double Taxation Convention 1981.............
In the case of Thailand, United Kingdom tax payable in accordance with this Convention in respect of income from sources within the United Kingdom shall be allowed as a credit against Thai tax payable in respect of that income. The credit shall not, however, exceed that part of the Thai tax, as computed before the credit is given, which is appropriate to such item of income.
So if the tax we pay in the UK on our income is greater than the tax we would/might have to pay in Thailand on that income.......we pay no tax in Thailand......and if it is lower we just pay the difference?
Is that how it works?