Hi Rob,
I couldn't find the family in any IoM censuses on Findmypast - you might have more luck with Ancestry.
The only household I found which looked possible, with the two Anns, was in 1841 before their marriage - except that John wasn't a shoemaker but a farmer:
Knockdoo, Michael, Isle of Man
1841 census
First name(s) Last name Gender Age Birth year Birth place
John Corkill Male 28 Farming 1813 Isle of Man, Isle of Man
Ann Corkill Female 40 1801 Isle of Man, Isle of Man
John Corkill Male 4 1837 Isle of Man, Isle of Man
Ann Corkill Female 0 1841 Isle of Man, Isle of Man
Jane McPhee Female 20 1821 Isle of Man, Isle of Man
Archive reference HO107
Piece number 1464
Book number 9
Folio number 29
Page number 3
I thought son John might have been born pre-marriage. However his baptism on 19 Feb.1837 was son of John Corkill & Ann Cowley. So wrong family.
Sue
: