Nope! It's much easier to get the Non Imm O in the UK. Why bother with the TR visa? Just get the Non Imm O, it makes life a lot easier when you arrive in Thailand.
Thomas Barnard No need for a 2nd passport and definitely not a reason for a 2nd passport as you retain your old passport through the application process.
No submitting your passport. You keep your old British passport. You send copies for the renewal, then take old and new passports to Immigration and they'll transfer extention of stay stamp and any re-entry permit.