I thought the shape and size of the so called 'sex marks'? at the base of the hindwing may indicate male or female, but I have no reference to indicate this at my disposal. I thought you may know.
In Michael Braby's Butterflies of Australia, there are illustrations of the male and female Meadow Argus, which can be differentiated based on the size of the sex mark. I haven't looked at this book since 2017 so I've forgotten how to tell the gender difference.
I checked Braby (2000) and it states 'the female is similar to the male, but generally larger, with the termen of the hind wing more rounded, and the apex of the fore wing less pointed. The sexes, however, are most reliably distinguished by examination of the fore leg'. Interestingly the species profile on page 574 only has one specimen photographed to cover both sexes.