You can search for details of Tasmanian ancestors at the tasmanian archives
http://www.archives.tas.gov.au/nameindexesThere is a convict John Pulford arriving in 1836 who could be your man. He came on a ship from London, unfortunately the Old Bailey records only go to 1834 online so not there at the minute.
There is a record for permission to marry for John Pulford and Emma Fowler, so this seems to be the couple Jenn found. John is listed as being free (if he was a convict his term may have expired). Emma arrived in 1844.
For a very reasonable fee the Tas archives will copy the records for you (or you can visit if in Tasmania & for a smaller fee copy them yourself

) The BDM registers to 1900 are also kept at the archives.
Seven children are listed on the Colonial families data base - the six Jenn listed & also Thomas 1849
There seem to be many grandchildren

Some of the children stayed in Tasmania.
Trish