That amount of cash will raise flags at every stage and is a security risk. You're better off losing a few £ on the transfer through a bank.

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.