The CASA requirement for the ratio of f/as to pax for Australian based carriers is 1:36. This is not per class but per aircraft.
This requirement has not changed to 1:50 (although other foreign based carriers are permitted to have this 1:50 ratio).
The legal requirement is 1:36
Qantas in all its different configurations, never has less than the legal minimum (obviously) and on certain configs even has a 1:26 ratio.