The whole idea of shorting this pair is mainly based on technicals and a bit of fudamental analysis:
Technicals:
Break and retest of both the trend line, and the support, as well as the 4H 50 EMA retest.
Fundamentals:
GDP GROWTH IS HIGHER IN AUSTRALIA,
INFLATION IS LESS IN AUSTRALIA,
UNEMPLOYMENT LESS IN AUSTRALIA,
the only thing against us here is interest rate that is higher in the UK.