William TUDGEY arrived as a free immigrant in Sydney per “Woodbridge” on 15 September 1838.
The "Woodbridge" departed Gravesend 25th April 1838, sailing to Cowes on the Isle of Wight to pick up passengers from Wiltshire and sailed from there on the 7th May 1838 (www.xroyvision.com.au/andrews/history/hist4.htm).
He worked as a surveyor and in Melbourne happened upon a newly arrived man who said there was a Tudgey family on his ship. It turned out that his parents Charles TUDGEY and Sarah TOPP had arrived in Geelong c1840 along with (?some of) his siblings (source: Early Families of Shepparton, Tudgey pages by Stephen Charles Bloomfield).
The date of William's parents' arrival is unclear and I have not determined on which ship they arrived. According to Sarah Topp’s death cert (1872) she was 25 yrs in Victoria (arr c1847).
The family farmed at Kew and William married Maria CLEMENTS on 24 Dec 1850 at St Peter's Church of England, Melbourne (Victorian marriage certificate). William's parents Charles and Sarah passed away (in 1866 and 1872 respectively) and were buried at Booroondara cemetery in Kew, Melbourne.
William selected 320 acres at Kialla East on the southern bank of the Broken River, moving there with his family and sister Rosanna c1875 (source: Early Families of Shepparton). Presumably the other siblings had already made their own way.
William's daughter, Sarah Jane TUDGEY married Edward BARRINGTON in 1878 in Kew, Melbourne (Victorian BDM index) on the 13 October (family records). They had ten children between 1880 and 1894 (Victorian BDM index, family records - see below).
As for the ancestors of Charles TUDGEY and Sarah TOPP, I've been in contact with Zillah Williams and Don Fraser (descendents of Charles' brother Henry) who kindly gave me a lot of information about the Tudgey family including the names of Charles' parents and grandparents and the details of his parents' marriage in Milford, Hampshire in 1789.