When Cathay Pacific joined One World, their services miraculously disappeared too.
To be fair to them, they didn't pull the route immediately. It went a few months after they started codesharing LHR-MAN on BA, not codesharing on MAN-HKG (via AMS/FRA/CDG, though I'm sure a 3 weekly non-stop may have become a slightly better product to offer from here given codesharing) and lack of general promotion of the MAN-HKG service.