Correct me if I'm wrong, but as a UK citizen living in Thailand you are not taxed on your worldwide income. And in Thailand you are only taxed on what you transfer in to Thailand, minus at least 210K first in deductions. But if you move back to the UK you will then be taxed on your worldwide income, right? So moving back to the UK would cost you more in tax, not less, right?
Anyway, 2, 3, 4 I agree with.
5 would be a good reason to stay!