Dear Grasshopper, I highly recommend that you go here RootsChat. Register as a new user, it is a free site also. Then goto their Emigrants to Australia board. See if you can find the topic mentioning 'Tasmanian Pioneers Index Lookup'.

Surely more details will be found on Death Certificates, then you can work your way backwards to England and then find this particular CHAPMAN family on Census records.

Please include in your journals what his wife's name was.

Editor.

Thanks allycat, I've just registered at RootsChat and will try my luck there.
P.S. I've updated the journal as suggested, thanks.