Vic, you can play around MEL - SYD - DXB - CDG, in one tix, the time to transit SYD might be quite short.
Granted it earns more Qpoints and QF SC, and the price difference might not be that much, but if you love lounge visits as I do, I find those connected flights do leave the lounge time available quite limited.
Indeed, I might be talking bull, and that there might be flights leaving MEL at 10am, all for the time same price in Sale J to get to SYD in time to meet the departure of that EK flight to DXB.
Personally, I have found ADL - SYD - NZ in Sale J might be bearable, but the lounge time in the QFi SYD J is quite short, so a lot of the time, I transit SYD overnight, ADL - SYD in red E fare, and then J across to NZ on the EK plane, either to CHC, or EK SYD - AKL before that flight that has now been cancelled.
Ok, I will now leave this post, as is, having put my point forward to avoid LHR if at all possible, Gbp150 in J for that APD! Ouch.