Anonymous participant 674 I'm not aware of any rule change, it's been the case that you can't get a 5 year licence on a tourist visa, which the DTV is.
The NI you pay in the UK is irrelevant. The tax you pay in the UK on the income you bring into Thailand can be claimed as a tax credit against Thai tax. The amount of tax you will pay in Thailand will depend on what allowances you can claim which are taken off before the tax rates apply then the tax scale applies. You might find this document useful