@Ian ********
Ok, I've spoken to my local Revenue Dept and Tax Advisor. If I remit my Government Pension into Thailand, it's only taxable in the UK, as per the DTA. Other income from the UK remitted into Thailand, ie rental income, private pensions are assessable in Thailand as well as the UK. The UK has first dibs, but the personal allowance of £12,570 we get in the UK counts for diddly squat in Thailand and so in my case I will be taxed in both the UK and Thailand and I'll end up paying more tax if I bring in other non government income into Thailand.. The DTA just prevents us being taxed on the same money twice.
It's a complex field and getting off topic but just something I wanted to point out so you can research further, so you don't get unnecessarily screwed for Thai tax. If you get an RAF pension and remit that into Thailand, I'm pretty sure that would be exempt from Thai taxes as it's a Government Pension.