Thank you for your reply Marie. My Mary McCart/McCarthy came to Australia before 1861 (with siblings?), but shipping lists don't confirm "my" Mary. Please read
http://www.isle-of-man.com/manxnotebook/famhist/v09n2.htm
Letter to Editor (20 years ago!). She uses name McCart, McCarthy and Downie (Father Hugh's second wife's name).
If it is easier, my email address is jpalmer83@optusnet.com.au
Hope we can help one another. Genealogy is a long painstaking search for most of us, but what excitement when we discover an elusive ancestor