Is this the family you are interested in?
4056/1873 BROWN William m. BYRON Sarah TENTERFIELD
Children
21188/1875 BROWN William Henrik WELLINGROVE
William Sarah
13254/1876 BROWN William Walter INVERELL
William Sarah
14700/1878 BROWN Sarah E INVERELL
William Sarah
19143/1881 BROWN Peter INVERELL
William Sarah
19886/1882 BROWN Charlotte A INVERELL
William Sarah
23315/1884 BROWN Jessie INVERELL
William Sarah
Can you give the marriage details of these children please. That might indicate where to look for parents William and Sarah.
From marriage certificate, what occupation do you have for William, and religion...might be useful identifier.
William and Sarah Brown are rather ordinary names, and if William died and Sarah remarried, she could have another name at death.