Deirdre, I've found 7 children of Thomas Croghan/Crahan/Cawn and Mary Monks, not 6! :)
Born on Norfolk Is.
Thomas Jr 1797-Assumed dead in NSW after 1817 sentencing.
Born in New Norfolk, Tasmania
Orison 1811-possibly died as a child/teenager
Also, Robert Id be interested in your file too! (firstname.lastname@example.org