Not sure how to tell small bean bug from brown bean bug Riptortus serapes, but I think the small bean bug has cream stripes along the sides of its body while those of the brown bean bug are yellow
I now think Riptortus serripes (Large brown bean bug, LBBB) does not occur here. The ALA distribution map shows a coastal distribution for it, and no records south of Wollongong. I have now renamed all our LBBB sightings as Small brown bean bug (SBBB).