Expanded hind tibiae possibly indicate Drymaplaneta semivitta which is not listed in CNM. See http://www.padil.gov.au/pests-and-diseases/pest/main/136549 and http://www.bowerbird.org.au/observations/20343
Cath, I have looked at Rentz's 'A guide to the cockroaches of Australia' and agree the expanded hind tibiae eliminate the common D. communis from contention here. Both D. semivitta and D. variegata as having expanded hind tibiae, but both are indicated as being confined to s-w WA. D. semivitta has a dark head with a 'pale band between the antennal sockets', but unfortunately the front of the head is not visible in your shots.