I think I've just muddied the waters
So I've been trawling for children born to Margaret Cameron's with no father listed between 1869 and 1889 in Victoria. I found four births John reg 1874 at Batesford, Edward reg 1879 at Montrose, Colin reg 1881 Clunes and un-named reg 1882 at Montrose.
The most interesting find was a death: CAMERON, un-named male, year reg 1882, father unknown, mother Margaret Cameron, place of death Penshurst, age 11, Reg No:6516. The place and age were very interesting!
Well, I couldn't resist buying the certificate...
When and Where Died: 19 June 1882
Name: unnamed Cameron
Sex and Age: male 11 days
Cause of death etc: Peritonitis, magisterial inquiry held on June 20th 1882 by (names)
Name...of Father and Mother:not known, Margaret Cameron, unmarried
The Penshurst constable was the informant.
The baby was buried at Boram Boram cemetery on June 20, there was no minister present and the witness was Neil Cameron.
Where Born etc: Boram Boram, Victoria, 11 days in Victoria
Poor little thing
So there was a Margaret Cameron birth reg 1861 Penshurst to Neil Cameron and Mary Burke Reg No:14809.
She would be far too young to be May's mother of course, but very likely is the mother of the baby boy born and died 1882 because of the witness at the funeral and the Boram Boram connection (Glenoe was/is in Boram Boram parish).
Lightbulb moment though thinking about that - Peter could've been the father of the 1882 baby and that got mixed up over time with the May McIntyre story.
Like I said, I've muddied the water and still no closer to May's parentage!
Cheers, Marlene