Sorry you had a bad experience on BA.

QF is the obvious alternative, the Skybed has some good reviews, but many still prefer Club World. Horses for courses.

If you don't like the upper deck, then there is an easy alternative, er, fly on the lower deck. The forward cabin on BA has only 2-3 rows and is actually quite cosy in my experience.

The other alternative for LHR-SYD is with CX via HKG. In a nutshell, the seat is not so good, but the service will be better (complete with noise-cancelling headphones).