Looking for Robert Burnes IN Victoria Nsw

My sister and I are looking for our great grandfather Robert BURNES - we think he was born around 1858
but don't have his place of birth at present.

Robert was 43yrs old when he married Matilda HEPBURN (22yrs old) in Melbourne Victoria in 1901.

In 1906 Robert was a General Commission Agent but don't know who for.

8th Feb 1906 Robert and Matilda had a son - named him Baden BURNES (339/1906) born Women's Hospital Crown Street.
Don't know what happened but Matilda changed her son's name to Baden HEPBURN (also 339/1906)

We would really appreciate any help - We can't find any information on BDM NSW or BDM Victoria for Robert Burnes.
thanks heaps. Jalz