We're still on April 2016 ! Fares are not loaded till at least 11 months out... and 'specials' can be had all over the place... not just from MAN (the pesky APD ruins it for many)
Given the choice, I'd rather fly on the likes of QR over CX.. as their service and catering are better.
You have to be slightly imaginative when you want to save... £4250 on CX per couple is high...
I can do less than £3000 all in with a little imaginative planning.. in Business Class and probably on the dates you want..And to save around £1000 , I'm sure the schlep to another airport is worth it, don't you think?