While I was searching for your William I also found a few siblings. Just in case you haven't already got their details.

Name:Charles John Page
Birth Date:4 Jul 1883
Father's Name:John Page
Mother's Name:Annie Jergens
Birth Place:Kent Town
Registration Place:Adelaide, South Australia
Page Number:148
Volume Number:308

Name: Chas John Page
Death Place:Fitzroy, Victoria
Age:59
Father's Name:John Page
Mother's Name:Annie Jergens
Registration Year:1941
Registration Place:Victoria
Registration Number:2295
Estimated Birth Year: abt 1882

Name:Francis Danl August Page
Father's Name: Jno Page
Mother's Name: Annie Jergens
Birth Place: Melbourne, Victoria
Registration Year: 1889
Registration Place: Victoria
Registration Number: 14515