Michael Snr.'s age at death is 'Unrecorded' for search purposes, shows with a 'U' (you can tick a box on the front search page to show unrecorded ages at death - can't remember why this was so, maybe someone else can comment).
I've just found the family in 1861 in Dundee. Nothing in 1851 so looks like they came over between those years. All show as born Ireland.
Michael, 60, Widower, Dock Labourer
Patrick, 24, Dock Labourer
Margaret, 22, Mill Worker
Thomas, 20, Dock Labourer
John, 17, Jute Weaver
Mary Ann, 16, Jute Weaver
Michael, 14, Millworker
No clues therefore as to where they came from.
Monica