I've added 3 more photos, but I'm sorry, my camera isn't very good for a close up. The specimen has a vibrant green appearance and reddish looking stems, a bit like rhubarb. Cheers, Roy.
There are several species of Dysphania in SE NSW which have fruiting bodies like this. I think a specimen needs to be taken to the Botanic Gardens for a proper identification.
Dave Albrecht said "Roy - Your ‘Crumbweed’ specimen found its way to me for identification. It appears to be Dysphania multifida (Scented Goosefoot). See the following links for further information https://vicflora.rbg.vic.gov.au/flora/taxon/fac28f72-b830-4390-9c5e-0f751df5ed8e and https://keys.lucidcentral.org/keys/v3/plants_se_nsw.old_2019_01-11_delme/key/plants_se_nsw/Media/Html/entities/dysphania_multifida.htm.
Does this also apply to the ones on isaacs Ridge? I looked the other day and couldn't find any of the deeply dissected leaves, only a few tiny linear ones among the flowers and seeds. The plants seemed to be dying back so I don't know if they are perennial or not.