Helen's father is not named in the indexes so presumedly the marriage took place before August 1856 when this detail was added. The witness's names might be useful though.
The Dunwich Benevolent Asylum was in Queensland and he appeared as 'Edwin William' on electoral rolls but the death was registered as 'Edward William'.
South Australian immigration records have an Ellen SHIPLEY aged 18 with her parents and sisters arriving into Adelaide from Portsmouth in May 1853 on the 'Calabar'.
http://www.theshipslist.com/ships/australia/calabar1853.shtm...It may be also be relevant that in the following year a Mr and Mrs OTTAWAY and a Miss SHIPLEY arrived in Hobart from Adelaide on the 'Faith' in August 1854. Perhaps this was Edwin and Helen/Ellen (pretending to be married) and her sibling?
Is this the birth of a child in Tasmania in 1855 before they were married?
http://stors.tas.gov.au/RGD32-1-3-p705j2k