Canadair You don,t know what you are talking about with regard to double taxation agreements between UK and many countries.
What this means is that in B_B,s case as he was working in UK he should pay taxes there and if there is a double taxation agreement between UK and his country then he will not be taxed twice.That is the way it works and not as you suggest.
As for your comments re British Pilots working overseas then provided they are employed overseas they are not liable to UK tax but of course pay tax in the country of their employment. If they work in a country in the Middle East that has no tax then that is an advantage available to all,but of course in reality those airlines pay less in the first place because there is no tax so you are no better off.
Not a question of Halo,s at all