So Australia will go to war with China if they take a pop at the QE?
I really doubt it - there is no clear coalition of those willing to start any sort of barney with the PRC - especially in SE Asia.
You don't understand Australia's military history then. There is plenty of concern in SE Asia about Chinese power and there are existing military alliances that would come into play should China decide to use military force to take Taiwan. Like I said it is about more than the presence of a single UK carrier.