Originally Posted by
Genius1
Remaining sectors will definitely be cancelled - I'm speaking from personal experience.
Luckily, that occasion was a misunderstanding due to a cancelled flight by BA. You can read all about it in my HKG trip report

Ah!! Sadly this is what I was expecting to hear and be confirmed. The oddity of air travel fare rules. You buy a couple of products (sectors) decide not to use one, to the benefit of the seller (BA), and they stop you using the remaining products. I can understand if I walked out of the airport mid-route but we're on a stopover, so they'd know if I check back in or not and therefore not delaying or disturbing anyone.