Hi Tim. Yes, it's the same person. He was baptized 15 Jul 1792 Arbory, son of Thomas GELLING and Catherine CUBBON. He married Margaret HUMPHREYS 14 Apr 1825 Arbory and they had 7 children before Margaret died (buried 14 Dec 1840 Arbory). John then married Jane CRELLIN 30 Jun 1842 Arbory and 3 more children came along. Jane was buried 17 May 1849 Malew. I have all the children, if you'd like them. John's 1862 will is transcribed on the IOMFHS will site, but I don't see his burial on Brian's index.
Here's what I have for the 3 census entries for John Gelling. In 1841, he'd be between wives, and he's widowed a second time by 1851. Items in square brackets are my comments.
1841 census at Ballanowin, Arbory HO107/1463/3 1 7 pg 8 (464355)
John GELLING 45 Farmer Y
Elizabeth GELLING 15 Y
Catharine GELLING 10 Y
Thos GELLING 8 Y
Robert GELLING 6 Y
Margret GELLING 4 Y
John GELLING 2 Y
>Jane WATTERSON 20 F. S. Y
1851 census at Mary Vale, Santan HO107/2525 502 pg 13-14 #48
John GELLING, Head Widr 59 Farmer of 119 acres occupying 3 labourers, b Isle of Man Arbory
Thomas GELLING, Son U 20 Farmer's Son, b Isle of Man Arbory
Robert GELLING, Son U 17 Shoemaker apr, b Isle of Man Arbory
Margaret GELLING, Daur U 15 Farmer's Daughter, b Isle of Man Arbory
John GELLING, Son U 13 Scholar, b Isle of Man Arbory
Jane GELLING, Daur 8 Farmer's Daughter, b Isle of Man Arbory
Anne GELLING, Daur 6, b Isle of Man Arbory
Richard GELLING, Son 4, b Isle of Man St. Anne
John MOORE, Son in Law Mar 42 Ag Lab, b Isle of Man St. Anne
Catherine MOORE, Daur Mar 22, b Isle of Man Arbory
John TATE, Serv U 25 Farm Serv, b Isle of Man Douglas
John ROGERS, Serv U 44 Farm Serv, b Ireland
Jane STOWELL, Serv U 17 House Serv, b Isle of Man Lonan
1861 census at Arbory Road, Malew RG9/4424 96 pg 17 #89 (543281)
John GELLING, Head Widr 69 Farmer of 25 acres, b Isle of Man Arbory
Richard GELLING, Brother Un 55 Farmer of 40 acres, b Isle of Man Malew [odd .. he should be about 61]
Robert GELLING, Son Un 27 Works on Farm & ?, b Isle of Man Arbory
Margaret GELLING, Daur 25 Works at home, b Isle of Man Arbory
Anne GELLING, Daur 14 Scholar, b Isle of Man Arbory
Richard GELLING, Son 13 Scholar, b Isle of Man Santon
Elizabeth MOORE, Granddaur 4, b Isle of Man Santon [d of Catherine]
I think this will be second wife Jane Crellin in 1841:
1841 census at Ballagarvin?, Arbory HO107/1463/3 1 12 pg 19 (4643355)
Jane CRELLIN 70 Ind Y
Jane CRELLIN 27 Y
>James KELLY 2 Y
Going back a generation, I have Thomas GELLING marrying Catherine CUBBON 7 Jan 1792 Malew and they had 13 children. John is the eldest. Thomas was buried 1 Sep 1835 Malew age 75 and his will is transcribed. Catherine lived on past the 1851 census, buried 27 Nov 1854 Malew age 84, with a will that's also transcribed.
Here's Catherine's census information:
1841 census at Bi??oan, Malew HO107/1464/3 3 34 pg 4 (464356)
Catharine GELLING 70 Y
Rich'd GELLING 36 Farmer Y
Wm GELLING, 33 Joiner Y
Jas GELLING 26 Joiner Y
Ann GELLING 29 Y
Elr GELLING 20 Y
Jas OATS 25 M.S. Y
Elizth CORKILL 5 Y
1851 census at Billown, Malew HO107/2526 108 pg 28 #111
Catherine GELLING, Head Widow 80 Farmer's Widow, b Isle of Man Arbory
Richard GELLING, Son 47 Farmer, b Isle of Man Malew
Ann GELLING, Daur U 39, b Isle of Man Malew
Robert GELLING, Son Mar 34 Joiner, b Isle of Man Malew
William KENNAUGH, Grandson U 21 Employed on the Farm, b Isle of Man Malew [s of Sarah, deceased]
Joseph KENNAUGH, Grandson U 15 Scholar, b Isle of Man Malew [s of Sarah dec]
John CORKILL, Grandson U 13 Scholar, b Isle of Man Malew [s of Catherine]
Ann GELLING, Granddaur U 8 Scholar, b Isle of Man Rushen [d of Robert].
I don't know who Thomas Gelling (b ca 1760) parents were, but I'd hazard a guess that it's one of the many John Gelling's of that time.