I don.t see how this varies from P. arabella ?? https://inaturalist.ala.org.au/observations?place_id=6744&preferred_place_id=6744&quality_grade=research&taxon_id=514524
See text and photos on page 62 of 'Moths in the ACT' (Cocking et al 2022): 'Philoboata arabella is a common coastal moth from southern Queensland to southern NSW. An unmamed close relative which has a slightly different as well as variable forewing pattern is present in the ACT. Note the coloured edge of the costa outside the longitudinal dark band. The adults emerge in the spring and are commonly seen flying in the daytime in October in both the bush and surburbia'. That is the reason we have been consistently naming these ACT moths: 'Philobota undescribed species near arabella'.