Hi, Shambles - this message indicates there is a song titled "Matthew Hopkins" or "Mathew Hopkins," but I don't think the person who posted the message is a regular Mudcatter.
Vincent Price starred in a 1968 film called Matthew Hopkins-Witchfinder General.
This Google Search will lead you to lyrics for several rock songs on Old Matthew, but I didn't see anything in the folk genre.
-Joe Offer-