I used one example from each of 3 websites, you need to exhaust all three before moving on
For example
PRONI
1766 Religious Census
Surname : Boggs
Forename : John
Townland :
Parish : Magherafelt
County : Londonderry
Religion : Established Church
Number in Family :
Original Documents : The original documents referred to in this index DO NOT exist. No further information, other than that recorded above, has survived.
From that one clue I would attempt to acquire everything to do with Church of Ireland records in Magherafelt civil parish
Magherafelt
Diocese of Armagh
Churches:
Magherafelt, St Swithin - view a map of this church
Website:
http://www.armagh.anglican.org/index.php/parishes/?page_id=195Clergy:
Rev Canon Terry Scott - Incumbent
The Rectory
1 Churchwell Lane
Magherafelt
Co Londonderry
BT45 6AL
Another google search produced
www.billmacafee.com/churchrecords/churchrecordsderry.xls182 Magherafelt Church of Ireland Christ Church, Castledawson. Formed out of Magherafelt parish and added to Ballyscullion parish – see under BALLYSCULLION Derry Loughinsholin
183 Magherafelt Church of Ireland St. Swithin's, Magherafelt. Baptisms, 1718-93 and 1799-1895; marriages, 1720-1845; burials, 1716-71 and 1799-1893; vestry minutes, 1718-95 and 1798-1909; confirmations, 1833. MIC1/1A* [CL 126] Armagh Loughinsholin
184 Magherafelt Church of Ireland St. Swithin's, Magherafelt. Baptisms, 1895-; marriages, 1845-; burials, 1893-. In local custody Armagh Loughinsholin
185 onwards covers the other denominations , one or two have early records. You might need to check all by the time you are finished.
I wonder if familysearch.com microfilmed some of these records and have since transcribed them on line. They have a website that lists the batch numbers of a single church. Going direct to the local clergy often doesn’t work but if you don’t try etc etc
Anyway I have run out of time
Good luck onwards JimG