According to the latest Thaiger news briefing 9 September 2024 UK retirees coming to live (or living) in Thailand are NOT taxed and no doubt any new law will reflect UK retirees do not have to pay tax here.
"Does Thailand tax expats?
Thailand does not impose tax on your income earned in the UK if you live in Thailand. You remain liable for UK taxes as a British citizen. Since Thailand and the UK have a double taxation agreement, you will not pay tax in both places on the same income. If your income comes from sources within Thailand, that may attract local taxes."
Retiring in Thailand for British citizens | Thaiger (thethaiger.com)