There are 25 daily flights between the UK and the UAE, 21 on UAE carriers and 4 on UK carriers, giving UAE carriers the advantage.
Not sure that is a fair comparison. UAE has two hub airports in DXB and AUH, both connected to UK regional airports as well as to LHR.
A fairer comparison would be between the UK (or essentially London) and the Arabian peninsula as a whole, where the scales start to tip the other way.
I can see a big loss of prestige for BA pulling out of SYD, but as always, this is going to be based on commercial logic, not political aspirations.
Why would VS be able to sustain a kangaroo route if BA couldn't? Lower crewing costs trumping BA's connections advantage? Perhaps that is key on a route with two long sectors?