This is a worked case study and is intended as a supplement to the related question Finding Devon parish marriage records?.
There are two different websites which offer help with determining the location of the Anglican church where a marriage took place by entering the GRO index reference.
Surname Society Church Marriage Finder
The Surname Society offers a Church Marriage Finder -- about their databse, the site says:
The database contains details of marriages between 1837 and 1911 and is not yet complete.
We currently have data from the following registration districts: Bermondsey, Bishopsgate, Bloomsbury, Braintree, Camberwell, Chelsea, Clerkenwell, Colchester, East London, Farringdon, Fulham, Holborn, Islington, Lambeth, Marylebone, Medway, Newington, North Aylesford, Poole, Poplar, Southwark, St George Southwark, St Giles, St Luke, St Saviour, Strood, West Ham, West London, Westminster, Westminster St Margaret, Witham.
GOONS' Marriage Locator
The Guild of One-Name Studies (GOONS) has a Marriage Locator Database which also allows you to enter the GRO index and deduce where the marriage took place. However, their website cautions:
The Marriage-Locator Database currently contains 613,844 marriage-locator > points (of which 327,679 are 'cardinal points') in 1,336 Registration Districts.
This is still a work in progress, and not all the data needed for all marriages is yet available. New data is continually being added.
Their statement of Marriage Locator - the principles explains how the locator works -- it is similar to the process described in What "hidden" clues are there in the GRO Indexes of births and deaths?
The marriage I want to know more about is an 1878 registration for Hannah Knowles. The marriage was registered in Kingsbridge (Devon) Registration District, Vol 5b Page 328. Ancestry lists the following people for that page:
Name James Bickford Edward Edwards Hannah Knowles Elizabeth Stone
The Surname Society's Finder is not going to help because the database does not have entries from the Kingsbridge RD. When I entered the GRO Reference into the GOONS Marriage Locator, I got the following message:
Marriage Locator Search Results
GRO Index: 1878 quarter 1, volume 5b, page 328:
Sorry, we cannot locate the church for this marriage. The entry is located between entries for Stokenham (RD: Kingsbridge) and Newton Ferrers (RD: Plympton).
Their principles page explains how the volunteers build up the database:
For each of the churches within that RD, they take the following steps:
First, identifying the earliest marriage in a quarter for a church, and noting down the names of the bride and groom.
Doing the same for the last marriage in the quarter.
Finally, using an online service, or FreeBMD, to find the page numbers where those two marriages have been indexed. These two page numbers, representing the first and last marriages in a quarter, are what have been termed the "Cardinal Points" for that church.
The widow Hannah Knowles that I am looking for is associated with Aveton Gifford. I have access to images to the parish register via DevonFHS. Can I use this information to cross-check the GOONS marriage locator, to see whether they have already established the "Cardinal Points" for that register?