Just thought I'd post this for the comedy value....

Called QF for clarification. Call transferred through to Australia.
I asked the very helpful lady if she was familiar with the OWE
rules for itineraries originating outside Australia which she said
she was, so I posed the SYD-PER-DRW-SYD question.

After ten minutes on hold she came back to say that no this
wasn't allowed and if she was me she'd go to Broome. So I
asked, given that I intended entering/exiting SWP through
SYD and would've flown SYD-BME how she proposed I got back
from BME to SYD.

Another ten minutes and she comes back to say 'Yeah, you
can fly back from BME to SYD. We wouldn't just leave you
there!'

Pure Genius.