I wonder if Thomas is son of Thomas Bell + Ann Craine bapt Bra 1830-04-09 - Anne would appear from 1841 census to be somewhat older than Thomas (tho ages had somehow equalised by 1851) m Bra 1828-12-30
with Thomas son of Wm Bell + Elinor Shimmin bapt Ger 1800-01-05
Ann looks likely to be dau of Robert Craine bapt Onchan but not 100% sure of mother as Onch reg not good (and adjacent parish of Lonan almost as bad)
Ann + Thomas are in 1841 census with 2ch Thomas + elinor at kerrow garrow

I suspect wills are your only route to verify these