I have a great interest in the NORTHEY name originating in the Chacewater/Kenwyn/Kea/Gwennap/Truro area of Cornwall which I believe is where you'll find Jane's ancestors.
You don't specifically say what you're looking for or the ballpark age of this Jane NORTHEY but in looking at some online resources, I'd suggest this possibility:
Marriage Sept quarter 1889 Newcastle Upon Tyne with choices including Jane Polkinghorne NORTHEY and Joseph STAMP
Then looking in the online 1881 census at familysearch.org there is a 9 year old Jane P NORTHEY born in "Shutton Durham" in the household of a 43 year old Richard NORTHEY with his birthplace given as "Creegbrose", Cornwall. This would be Creegbrawse near Chacewater, Cornwall. Other family members were born in Todpool and "Chasewater" which are also in the area where I research NORTHEYs.
I will have to look into my records further but believe that Richard's marriage to Grace was not his first. There is a marriage record at FreeBMD in Durham registration district December quarter 1869 which has choices of Richard NORTHEY and Grace WILLIAMS and I think that these may be Jane's parents. (Of course a birth certificate would be definitive!)
If interested in going back further or if you need hints on Cornish research let me know. I don't know if that's already known to you or not. If not, it's a very fun area to research with alot of free online resources available including censuses.
In the online 1841 Cornwall census at http://freepages.genealogy.rootsweb.com/~kayhin/cocp.html
you'll find a family in Creegbrause, Kenwyn enumeration district 15 with a 4 year old Richard and parents, Richard and Jane. As I recall off the top of my head, these would be Richard NORTHEY and Jane POLKINGHORNE and the paternal grandmother's maiden name could perhaps account for Jane's middle name assuming I'm right about that 1889 marriage.
I have alot of notebooks that I could look into in more detail if you're out there and interested.
Karen in Pennsylvania, USA