Well, as you probably are aware, there were 10 registered births to this couple.
However, there is discrepancy in the age given on various records for Catherine (nee SNELL)
Baptised 1833, at what age we do not know.
Age at death 82 so born 1824
Age on the shipping record 20 years. Domestic Servant.
Cathe SNELL
Arrival Age 20
Birth Date abt 1835
Departure Place Liverpool
Arrival Date 27 Apr 1855
Arrival Place Geelong, Australia
Ship Epsom
Going to William Butler at Little Myer Street.
Still bearing children in 1880 according to the registration index.

You will need to purchase a certificate or two I think.
I do not see a marriage record, but the certificate for the birth of a child will show-
Name
Date
Place
Father's name
Father's occupation
Father's age
Father's birthplace
Mother's name
Maiden name
Mother's age
Mother's birthplace
Marriage date
Previous children
Sue