HBA/CHC
Very strange that I remember this, but I'm fairly certain that when TN operated the HBA to CHC service it also carried a QF flight number (in those days they were known as 'Joint' services rather than 'Codeshare'. QF around that era was a single type 747 only operator (may have been introducing 767s) so HBA to CHC would have not been viable in a 'Jumbo', therefore the route was palmed off for TN to operate.
Also remember Mum and Dad travelling to Portugese East Timor on an international TAA Heron.
So obviously not all international sectors were the sole preserve of QF.
Regards,