The snippet was indeed quite a find!
I have this particular book, and regarding its veracity I can only say that when checking references within it I found seven straight transcription errors from printed books within the first five pages.
I will check this page, but most likely from experience he is quoting from the Gentleman's Magazine itself.
As I said, I doubt this is even my direct line, but I may just ask someone on the Norfolk boards to look up Merton's register and see what they make of it.
Edit:
I just checked the Book from Google Snippets (Notes and Extracts etc of Bukenham/Bokenham by Henry Maudsley).
This is from a letter sent to him, so is probably an entirely different transcription, as opposed to an erroneous copy from the Gentleman's Magazine.