QF will not interline to QR on separate PNR's. You can ask polity, but expect to be declined
QF- no checking of luggage separate itineraries from 1 Sep [2016 some exceptions]
https://www.qantas.com/agents/dyn/qf...hecked-baggage (click "through checked baggage")

There is also a free landside bus T3/T2 to T1.

A taxi driver will not be happy, but they should not refuse a fare. They can wait a long time. Would be the 1 time where a good tip would help.

If on the off chance QF CBR do interline checked baggage you can get the (free) QF airside bus from Gate 15 (inside security) to T1.

Before the silly "no interlining on separate tickets" was introduced it would have been easy.