Hello Colin,
A search of the IGI doesn’t show a marriage for, John Corkill and Jane Mylrea.

1881 Census
Source Information: Dwelling 6 Fancy Street
Census Place Onchan, Isle of Man, Isle of Man
Family History Library Film 1342346
Public Records Office Reference RG11 Piece / Folio5603 / 46 Page Number7

John CORKILL 47 Lonan, Isle of Man Retired Farmer
Jane CORKILL 40 Lonan, Isle of Man
Mary Ann CORKILL 10 Lonan, Isle of Man Scholar
Emily Jane CORKILL 8 Lonan, Isle of Man Scholar
John James CORKILL 6 Onchan, Isle of Man Scholar
Thos Edward CORKILL 1 Onchan, Isle of Man

2 Baptisms for Jane Mylrea born Lonan – for you to search,

Jane Mylrea 23 JAN 1842 Lonan, Isle Of Man
Father: Thomas Mylrea
Mother: Ann Kelley

Jane Mylrea 13 FEB 1843 Lonan, Isle Of Man
Father: William Mylrea
Mother: Jane Killip

here are John CORKILL and Jane MYLREA their Childrens Baptisms,

Mary Anne Corkill
gender:Female
baptism/christening date:23 Oct 1870
baptism/christening place:LONAN,ISLE OF MAN
father's name:John Corkill
mother's name:Jane Mylrea

Emily Jane Corkill
gender:Female
baptism/christening date:01 Sep 1872
baptism/christening place:LONAN,ISLE OF MAN
father's name:John Corkill
mother's name:Jane Mylrea

John James Corkill
gender:Male
baptism/christening date:03 Aug 1874
baptism/christening place:LONAN,ISLE OF MAN
father's name:John Corkill
mother's name:Jane Mylrea

Thomas Edward Corkhill
gender:Male
birth date:02 Jan 1880
birthplace:Douglas, Isle of Man
father's name:John Corkhill
mother's name:Jane Mylrea Corkhill

don't forget to backup your computer !

Averil