Maggi,

It states that Eric Wilfred Cannell was born in Randwick NSW in 1919. You will need to do your research in Australia first before crossing the seas to IOM.

Suggest you acquire his RAAF records and/or his birth certificate to get his parents names, unless you already have these.

With this info, you may find his father was born in the IOM, or even the grandfather. To make your Manx research easier, you may need to know the parish too.

Till you get back to the Manx origin of your Cannell line, it will be very difficult for you to make that link to the Island. Cannell is a fairly prolific Manx surname.

Good luck
Elizabeth.