going via HKG was always seen as a bit of the long way round imho -
Check LHR-SYD on great circle mapper, it's actually the
shortest route, just 2 mi. longer than the great circle route (ditto LHR-CAN-SYD).
Great Circle Mapper=
the reason LHR-SYD flights went through SIN or BKK rather than HKG is historical: during the cold war overflying China
PR and the Soviet Union was prohibited, so the great circle could not be used.
BTW, via DXB is much longer.
Great Circle Mapper=