To answer Jean's question at the bottom of her note ....
My Cubbon knowledge is woeful at best, but I feel pretty positive that the Thomas Cubbon bp 10 May 1778 Braddan is the son of William Cubbon & Catharine Gelling of Bealyvear, who married 6 Dec 1763 Marown. And yes, Catharine Gelling (b ca 1740, bd 1811) will be the daughter of John Gelling of Ballig (ca1705-1784 MI at Marown - see Donna's note Jul 12/08 ) & Ann Fayle (bd 1791 Marown) and is an elder sister of Robert Gelling (1753-1815) longtime schoolmaster of Marown.
Frances's note of 14 Oct/09 has William Cubbon's parent's will extracts: William Cubbon 1771 and Jane Cubbon als Kinley 1777.