The latest edition of the Guild of One-Name Studies Journal, Vol 14-6, Apr-Jun 2022, has an article Marriage mining & the Loach tables. It relates to the civil registration index of marriages in England and Wales with relevance to the West Midlands.
In compiling the GRO indexes clerks followed a set pattern. Within each quarter of the year and within each Registration District, they arranged Anglican marriages before all others, followed by Register Office ones. Non-conformists followed. The Anglican churches were arranged in alphabetical order although an ancient parish church may have been given precedence.
So what’s a Loach table? Referring to the article that is the basis of the Guild article, Marriage mining in the West Midlands, given the GRO reference for a marriage in the area the page number in the Loach table for that Registration District, and entry for the year and quarter will indicate the church where the ceremony was performed.
It worked for me for an 1837 marriage.
These days you may well find Ancestry already has the information and an image of the marriage certificate so the technique will be of most interest if you don’t have that access.