Following on from Matthew's finding of the employer for William as John Charles STRACEY I thought Mr STRACEY would be worth a look. He seems to have been quite a businessman,
These sightings, of course, may not be the same man.
1838 bankrupt, insolvent, Hobart, John Charles STRACEY, auctioneer
1854 departure from Launceston to Melbourne Mr STRACEY, (no given name shown), cabin passenger. (This is from the Tasmanian Names site and I can't get the image to show so can't be sure)
1856 Electoral Roll, St Kilda (suburb of Melbourne)
John Charles STRACEY, Inkerman Rd, auctioneer, householder
There's quite a bit more on him but these mentions at least show that William may have known his former boss in Melbourne.
Judith