I agree its likely P. bistrigula. Moths of Victoria say distinguishing features for P. bistrigula ( in contrast to P. atra, cineriacollis and testaicollis) is that the base 'facial disc' or 'collar' colour at the front of the thorax is the same colour as the rest of the brown thorax. These moths have a prominent lighter reniform mark with a tail, and a lighter broad band across the termen of the forewing. Males of P. strigula are said to lighter and show more fine forewing features than the plainer, darker females.