Some new information to add to what I wrote here 10 years ago.

The John Gelling and Eleanor Crellin who married 5 Jun 1802 Braddan are likely the parents of all the children. [The other couple of the same names who married 13 Feb 1798 don't appear to have had any children.]
John Gelling was baptized 25 Aug 1771 Marown s/o Robert Gelling & Jane Kelly and buried Douglas St George 11 Sep 1833. Ellinor Crellin baptized 2 Mar 1774 Patrick d/o Thomas Crellin & Ann Quirk. Alive 1831 when she received an inheritance acknowledged by her husband. The 31 May 1840 burial age 75 of Eleanor Gelling fits better for age to the other Eleanor Crellin.

1. John b 1803. He died 27 Jan 1893 age 89 at Mechanicsburg, Sangamon Co, Illinois. His wife died 30 Dec 1872 age 83 same place. She was 14 years older than him. No children. He was a Farmer
2. Margaret b 1805. I believe she married a widower Edward Corkill 31 Mar 1832, 5 children. She died 1848 Braddan age 43. Edward is in 1851 census age 50 with 4 children.
3. Robert b 1807 was a widower when he married Catharine Cain in 1843. His first wife likely was Ann Kelly; they married 6 Mar 1834 Braddan. Ann was buried 8 May 1839 age 29. They had 2 children, Robert James 1835 and Frances Eleanor 1837, both died as infants. Robert died 1875 age 68 and Catharine 1880 age 67 Mechanicsburn Illinois. Robert was a Miner in IOM and a Farm Laborer in the U.S.
4. Catharine b 1808. No information. Possibly died early?
5. Thomas b 1810. Nothing more to add other than Agnes Brough was born abt 1820 in Scotland and died 1890 Maughold. Thomas was a Miller.
6. Isabella b 1813 died Dec 1843 Marown age 30 Spinster.
7. Charlotte Eleanor (Ellen) died 1889 Mechanicsburg age 72 Spinster..