Unfortunately I have little more information. I know for certain that Elizabeth Bailey and John Ruddock arrived on the City of Manchester 1851 in Adelaide. I am still trying to search out ships records from our State Library.
I do know that Elizabeth Ruddock (nee Bailey) died in Hilton South Australia on 17th December 1902 aged 83, which has her birth in 1819.Does that match up with your dates?
I have been searching for their marriage in Somerset and cannot find it at all. Unfortunately they left England days before the census was taken so do not appear.