Now I have received quite a few details, including 4 marriage certs for Florence. John St Clair, Horse Trader, Richmond, and Ellen Fogarty shown as parents. Florence was born Richmond, not St Kilda, according to the death cert. I'm still none the wiser as to the parents. The only ones who could fit in were only children in 1877.
The family story is that upon John St Clair's death, Ellen and Florence moved to Sydney and Ellen ran a boarding house for seamen. Florence's first 2 husbands were seamen. Lawrence Anderson and Olaf Olsen. Apparently when Olaf died, his friend, Carl Sundstrom, "looked" after the family, but as he was the manager of a firm the board weren't too keen on the arrangement, so they married in 1912, after a couple of children. She then married Sydney Sandry in 1919.
Can't find if Ellen ever remarried in Sydney, or where she died. Perhaps someone in the "Brains Trust" can come up with some ideas.