Hi Bruce,
I've gone around and around about Thomas' parents and am at a loss as to where to go from here. I have his wife as Catherine Kewley c. 1795 Patrick and judging by census data Thomas seems to have been born between 1800-1806.

1841, Arbory, district 1, page 5, Ballanorris
Thomas Cubbon, 35, agricultural labourer
Catharine, 40
John, 14
Thomas, 10
Robert, 5
William, 1
Ann, 16, female servant

1851 Arbory
Friary
Thomas Cubbon head married 50
Ag. labourer b Arbory
Cath. wife married 56 b Patrick
John son unmarried 23 Ag. labourer b Arbory
Robert son 14 Ag. labourer b Arbory
Wm. son 11 scholar b Arbory

1861, Arbory, district 1, schedule 62, Malew Road
Thomas Cubbon, head, married, 60, agricultural labourer, Arbory
Catherine, wife, married, 63, Patrick
William, son, unmarried, 20, agricultural labourer, Arbory
Anne Taubman, servant, unmarried, 40, house maid, Rushen
Matthew Christian, son, 10, scholar, Rushen

In 1871 I believe I have them living on Malew Rd close to their son Thomas' family
they are:
Thomas 71yrs fisherman
Catherine 78yrs
William (son) unmarried 26yrs mariner
Richard (grandson) 8yrs scholar

I believe Thomas and Catherine's son Thomas c. 1831 d.1873 m. Margaret Clugston (Rushen) in Arbory in 1858.
Children:
Robert c. 1859 d. 1873
Thomas c. 1863 d. 1932
William c. 1866
Catherine c. 1861
James c. 1868 d. 1916
John c. 1871
George c. 1873 d. 1917

I included all the above in case it rings any bells. Any information, insight/thoughts ideas on how to proceed gratefully received.

Ann