Looking at timetables dated July 1999 and July 2000:
Flight
1999
2000
QF52: SIN-BNE---Mo, We, Sa19:40-0510+1763
QF5: SYD-SINTu, Th, Sa, Su15:40-21:35744Tu, Th, Sa, Su16:40-21:35744
QF5: SIN-FRATu, Th, Sa, Su22:50-0535+1744Tu, Th, Sa, Su22:50-0535+1744
Note that QF5 departed SYD...