At best Concorde would take 18hrs to fly from the UK to Australia with 2 tech stops. (Bahrain and Singapore etc..)
18hrs in the small cabin of Concorde against 24 hrs in first class or club class, is a no brainer.
Concorde could be classsed as a short haul jet flying medium haul routes.
Very few people would pay to fly that sort of route, you could pick up a few pax that would only fly one of the sectors, but not enough to make it pay.
BA tried this with the 2 sectors out to Singapore in the lates 70's early 80s'. It lost shed loads and in the end was never extended all the way to Australia.