Hi Jane
I'm getting Kenneth's birth year c. 1826 from both the 1851 and 61 censuses. Is this Margaret's birth entry: 02 NOV 1827 Wick, Caithness, Scotland, with parents Alexander and Janet?
If so, this leaves a possible name for Kenneth's father of Hector, as name of first born son following their marriage in 1853.
Have you tried searching for the death cert of Kenneth in R & C?
Regards.
Monica