Hi Felicity,
Since I posted that message I've made a fair bit of progress researching these two. Nathaniel was actually born Nov 1808 in Liverpool. He married Hannah Rushton (1812-1861) in 1836, Liverpool, and they had 8 children. His father was Thomas Cain, merchant tailor and draper in Liverpool who I am pretty certain was born on the Isle of Man in c1756, died 1814 Liverpool. Nathaniel's mother was Ann Sproston (1774-1847) daughter of Nathaniel Sproston (hatter & hosier) who died 1792 Birmingham but came, I believe, from Chester.
Hannah Rushton was daughter of William Rushton (1769-1844), a very successful Liverpool merchant/woolen draper, and Phoebe Copley (1773-1833) who was daughter of a Leeds cloth manufacturer.
I have more, so let me know where your interest is and I'll se what I can find.
Thanks for the contact.
Oliver.