Thanks for that Sue. I hadn't thought of him going to Australia though that of course accounts for there being no records in IOM or UK for him!
I've only just come across this connection to the Radcliffe family - and they look a very interesting lot - but I'm really tracking down the Cavendish/Corjeag 'tribe'. JC Radcliffe's mother was one of the Kirk Michael Corjeags. Most of the later Corjeags, being female, changed their names by marriage, although I've heard their descendants still often have Corjeag as a middle name.
I would be very interested if you have any further information about this man's family/descendants.

Thanks again for your help.