I am looking for when Joseph Gell camt Australia. He married Joanna Marie Elizabeth Einsporn in Geelong, Australia in 1951

You would mean 1851. To the best of our knowledge Joseph Gell was a convict in Tas, In the 1830's. Came to Victoria after that. He was a talior by trade.
One of his son's ? was John William, Who selected the land for what is known as Paradise Valley, in Gippsland Victoria in 1884, Gell's are still there today.

Joseph Gell arrived in Australia as a convict, leaving Downs, England on 30.1.1836 on board the "Elphinstone".
Convicted in Warwick 17/3/1835 for 7 Years for Larceny before being convicted of a felony.
Left England 20/1/1836
1833 was tried for larceny & punishment was a whipping
Johanna Marie Elizabeth arrived in Australia in May 1851 on board the "Emmy"
I have Joseph's convict records if you are interested.
Please contact me at rmerritt@ymail.com