Well found Wivenhoe, so born circa 1879, so in 1896, he was NO YET OLD ENOUGH to give consent if Florence is a family member.
SO WHO WERE HIS PARENTS

Sands 1915 (so different from earlier source!)
Henry ST CLAIR, 281 Cleveland St, REDFERN
And NO entry for a Mrs Ellen SIMMONS
Sands 1892 Alpha (so different from earlier source)
Mrs Ellen SIMMONS, boarding house, 221 Cleveland St, REDFERN.
Sands 1909 Suburban
Cleveland St REDFERN
At 221 is a Frederick MAIDMENT
At 281 are Albert BUSHBY and Harold SMITH
Now errr WHO CAN find out IF Cleveland St REDFERN was renumbered between 1890 and 1915 …. I know that in about 1900, Cleveland St EVEN numbers was Sydney and ODD numbers was Redfern (and I suspect Darlington) and that the City of Sydney Council’s Boundaries were (still are) quite flexible.
Sands 1900 Suburban
221 Cleveland St (Redfern) Frederick MAIDMENT (it is between Walker St at 211 and Elizabeth st at 239)
281 is a George CHAPMAN (it is between Castlereagh and Pitt Streets)
Sands 1895
NO sighting for Mrs Ellen SIMMONS, but that’s the directory that has the John ST CLAIR at Burwood and the R T ST CLAIR as manager at Toohey’s Brewery. .
Cheers, JM