Ian, you didnt mention what you knew on your initial email. Was your Grandmother Catherine Jane nee Cowley, as that is who John A married?
If so, there are their children (to 1901) and one of them your parent and/or their siblings.
DOUGHERTY, Margaret Is 12 Dec 1897 Dou 1341 DOUGHERTY, John Alma COWLEY, Catherine Jane
DOUGHERTY, Mary Louisa 9 Jan 1899 Dou 1411 DOUGHERTY, John Alma COWLEY, Catherine Jane
DOUGHERTY, William Alf 8 Nov 1900 Dou 1544 DOUGHERTY, John Alma COWLEY, Catherine Jane
Sandra