Why roll the dice when the airline concerned may refuse to allow check in or the immigration officer on arrival may refuse entry. He might get away with it but then again he might not and lose money paid for tickets and accommodation.
Airlines can be fined for bringing in passengers without the correct documents and it's possible that they have set 6 months in their system to be on the safe side.
When you check in, the passport is swiped and under 6 months validity flags up on the computer. You aren't getting any further. It happened to me going to the Philippines after COVID, I was one day short of six months remaining.
The flight from Newcastle has a number, it goes to Dubai not Bangkok and it may confuse the system so use the flight number from Dubai.
If you transited through Dubai without going through passport control, you originally boarded in Newcastle. If you went through passport control and had a stopover, then you boarded in Dubai.
The reason for this is that if you are refused entry, you are returned to the last country that admitted you in rather than your country of citizenship. Eg. a Nigerian arriving in Sydney on a direct flight from New Zealand who gets refused immigration clearance gets sent back to NZ. If he arrives from Lagos on a flight with a transit in Dubai, he goes back to Lagos. If he had a Dubai stopover, he would go to Dubai. If he gets refused entry there, immigration would require Emirates to take him back to Nigeria or a third county willing to admit him.
There are protocols and agreements in place for all this.