Raymond,
If Jane was baptised in 1805 and married in 1820 then she was only 15 when she married. That was possible, but pretty unlikely.
There were exceptions, especially in the early years of the Royal Irish Constabulary, but normal RIC practice was to not to post an officer to a county where he or his wife had family connections. (His RIC service record should show his county of birth). Was Daniel moved from Kilrea to Muff after his marriage? If so, that probably tells you his wife came from Co Derry. If she came from Co Antrim there would have been no need to move him.
And if the couple married in Dungiven, I would wonder whether the bride came from there. Tradition was to marry in the bride’s church. So in the absence of any other harder information about her origins, I’d be inclined to search that area. Dungiven is a small town 50 miles from Belfast. Why would a woman from Belfast marry there unless she lived there?
You haven’t said what denomination the marriage was but I am guessing Church of Ireland. The PRONI guide to church records indicates that it’s the only denomination in that parish with any records that far back. They start in 1795. My guide to Church of Ireland records says that rootsireland has some years for that parish but not all. So possibly they don’t have the early baptism records. I don’t know. PRONI has a full copy of the records but they are not on-line and so a personal visit is required to view them.
Be aware that not all churches have records for the time of Jane’s birth. She was probably around 20, that was the normal sort of age to marry, so born c 1800. And of the churches that do have baptisms for the early 1800s, many are not on-line, especially many protestant records. So finding someone of the right name on rootsireland or the UHF (who share the same records by the way) does not mean that was the only Jane Downey in Ireland at that time. I searched the 1901 Irish census for Jane Downey/Downie and found 44. The name would have been equally prevalent in 1800.
The geographic distance and the fact that the Belfast girl would only have been 15 makes me doubtful she’s the right one.
The only factor that goes against what I have said about Dungiven being more likely to be where Jane was born is that I cannot find any Downey/Downie families in Dungiven in the 1831 census (which has survived). The name is found fairly widely in Co Derry but not in Dungiven. So maybe she came from somewhere else in Co Derry and work took her to Dungiven. Did she come from Kilrea perhaps, as Daniel was serving there? How else would they have met, I wonder.
There was a George Downey living in Caraloon, parish of Kilrea, in 1831 (family of 3, all Church of Ireland). Is George a family name?
http://www.census.nationalarchives.ie/pages/1831/Londonderry/Loughinshollin/Kilrea/Caraloon/54/
Possibly DNA testing may be a way of matching with others who have additional information about where the family originate. Family Tree DNA reportedly has more people with Ulster roots than any other company. That obviously increases the chances of finding a match. You might want to try them or, if you have already tested, you can transfer your results to them for no fee.
The North of Ireland Family History Society is running an Ulster DNA project in conjunction with FTDNA and can offer testing kits at a reduced price. http://www.nifhs.org (Go to DNA project on the website).
