First many thanks to everyone who has taken the trouble to reply - I now know what he looked like and what happened to him - it looks as if he may have died in 1901 at the great age of 81. I've found out from the wonderful Fremantle Prison website that the only other George Pearson who was a convict was 13 years younger.
Details about my George
He was born in Spratton, Northamptonshire in 1821, parents George Pearson and Sarah Blencowe. He married a Caroline Cox and they had 4 children. He managed to be out of prison for the 1861 and 1851 england census entries. He travelled over on the York arriving 31 Dec 1862. The Fremantle site has him listed as married with 2 children - but he left a wife and 4 children behind in Banbury, Oxfordshire, all of whom lived for many years, so I suspect he remarried and had more children in Australia. It also lists 2 possible deaths, 1890 or 13 Sep 1898 in Mt Eliza (but the only Mt Eliza I could find is near Melbourne and that's a long way away) and the death that Rhonda found in 1901 age 81 does fit him exactly. If anyone else would like to find out more about his life in England and the full gory details of his crimes and trials it's all transcribed on his profile page and as stories linked to that page. Just search on ancestry for George Pearson born 1821, Spratton and my tree is called Pearson/Pigg.
Obviously I'm extremely interested in the possibility of some Australian distant relatives if he did have children, and it would be lovely to let them know about their English roots - both the Pearson's and the Blencowe's go back a long long way with exciting things like ancestors that had Coats of Arms.

One last thing - if any of you so kind to help me out have English ancestors from the Northumberland/Durham area of England then I'll be happy to look up information for you at our local record centres. I also have lots of information about Northamptonshire and bits of Yorkshire so although I have to travel to get there I already have a lot of info at home.