Just got back, with a Tax ID, same number as on my Pink Card. with assurance that, in my case, transferring 40k per month = 480k per annum, after 190k + 60k + 150k all at 0%, I shall have to pay Bht4000 for the year. There was some mention of 100k being deductible for expenses. As we are not married, I cannot claim 60k for my Mrs, but possibly some for the school fees I pay for my Mrs's son, he will let me know.
Where the money comes from, pension, interest, sister's immoral earnings, is of no matter. It is simply how much is/will be transferred from UK to Thailand in the specific tax year.
As I am only getting UK State Pension @ £170 per week = £8840 and a small one from Norway, my total UK income is £10400, below the Tax Free Allowance, so no tax due in UK either. I am happy with this.