Tod,
In your opinion (only), what would you do.
Dual nationality kids.
Thailand to UK (first trip)
1: Passport control: Leave on Thai Passport, enter UK on UK passport? Vice versa? Doesn't matter?
2: Passport details for online ticket purchase: Thai passport details, UK passport details, Doesn't matter?
Not holding you to this whatsoever - just your opinion.
Cheers.