Apart from the unconfirmed information you are using -
What is the earliest evidence you have of your great grandfather eg. name on a passenger list, name on a marriage certificate, father on a child's birth certificate etc.
What certificates do you have for BDM events in the life of Robert Francis TALBOT in Australia?
What state of Australia?
Have you seen the written history that he made of his life?
I actually have a lot of info on him once he settled in Australia, the Problem for him is where he was actually born and the most important part is about his parents. This is an area that nobody can find any information about.
The earliest info is a Navy registration held at the archives which states reference ADM 188/60/73294.
Name Talbot Robert Official Number 73294, place of birth Tannavaid, Tipperary, Date of birth April 1842.
There is also a census of 1861 where it states; Robert Talbot - Royal Navy at sea and in Ports Abroad, Male - age 19 - single -2nd Class - Birth 1842 Ireland
I also have a copy of a list of Officers, Crew and Marines aboard on the night of Sunday April 7th 1861 where it states:
Robert Talbot - 2nd Class - single - aged 19 - Tipperary, Ireland
His memoirs were rewritten by his one great Grandson and I have a copy of it. It was also in the Newspaper.
He was aboard HMS Clio in 1870 in Australia, upon the end of the 3 years they returned to England where he was paid off and returned to Australia aboard Barque Jerusalem.
Marriage certificate states:
4th Sept 1873 - Robert Francis Talbot - Batchelor - Ireland - Steward, HMS Clio - Sydney - William Talbot (professor of music) & Hannah Mary Watts
Death certificate states: his name as Robert Francis Talbot, Father William Talbot (Farmer) and where born as Malahide, Dublin, Ireland.
These entries had been by his Leslie Talbot