Ok give me a destination and a date, both go via the sand pit and one will require a "Jetstar booking" so yes I need to book 2 flights to save about $2,000.
1 = a return Darwin - Singapore around $300 = A Singapore, sandpit, pick your place London return at about $1,200.
The other is an onshore booking Darwin - London (sorry I did not pick a specific airport) and minimum cost is $3,660.
Now if very big on dates and stuff is vital in 3 months (I doubt) they both leave Darwin, both go Singapore, both go Dubai and both go London (sorry refer my airport location).
So explain Australia is = or even similar on costs using same airline?
As I said I will use other dates and times and shift the destination airport a few miles.