Benjamin Parker senior (c1832-1903)
He was from Barkway, County Hertfordshire in England. He died at Tooborac, Victoria on 6 July 1903. He is known to have arrived on the Victorian goldfields early in the goldrush. 
The ship London left from London, England on 22 February 1852, then from Plymouth on 5 March, and arrived at Point Henry, Geelong on 2 July. 
There is a shipping record – line 241 on page 233 Book 5A of Assisted passenger lists (1839-1871) – indicating that a Benjamin Parker, an unmarried male aged 20, arrived in Geelong on the ship London in July 1852. He is listed as a shepherd from Hertfordshire , religion Episcopalian, could neither read nor write, paid £2 for the voyage, had no relations in the colony, had no employment awaiting him on arrival in Geelong.
A similar record on line 220 page 102 Book 8 shows a Benjamin Parker, agricultural laborer of Hereford, religion Church of England, could neither read nor write, age 20, travelling ‘on own account’ which appears to mean that he had no pre-arranged employment waiting for him. This second record does not appear to be of my ancestor as his county is shown as Hereford (assuming it was recorded correctly).
Benjamin married Elizabeth Nunn (c1833-1889) from Westerfield, Suffolk on 21 December 1854 at Christ Church, Geelong.
It is known that Benjamin returned to England within a short time. 
He returned to Australia soon after with his mother Maria Parker (nee James) and 3 or 4 of his brothers. (ref. Obituary in The McIvor Times & Rodney Advertiser 9 July 1903)  
Line 242 on page 413 Book 11 of Assisted passenger lists (1839-1871) shows Maria Parker, occupation housekeeper from Hertford, religion Church of England, able to read and write, 58 years old, ‘with her sons .?. Parker to Ballarat’. Her ship Tudor left Plymouth on 28 March 1857 and arrived in Melbourne on 30 June. Also on the list was John Parker laborer of Hertford, Church of England, could read and write, 16 years old, travelling on own account to Melbourne. He was possibly Maria’s son. No other Parker was on Tudor passenger list.