P&O and Cunard have world cruises that always visit Sydney. They leave UK early Jan each year. It is possible to travel out on one ship and return on another so you would need to look at the timings to see arrival and departure dates. Brian.
Thats easy. Just contact www.CRUISE.co.uk and they will arrange an outbound on one line and a homebound on either a different ship or cruiseline, with time in between. Indeed, you could probably work it out yourself by looking at the P&O, Cunard and Saga website itineraries. Good luck. Richard.