Gospel grinder

One who grinds something, such as the teeth.

(slang) Any tooth.

(UK, slang, pejorative) A person who persistently promotes religious beliefs to others, even when unwelcome.

(slang) A church.

A gospel shop is old-school slang for a church — the kind of irreverent nickname that suggests the speaker views organized religion with a slightly skeptical or at least irreverent eye. It frames religion as a business or storefront selling salvation, which gives the phrase a wry, working-class edge. You'd more likely hear it from a cynical narrator in a Victorian novel than a modern podcast, but it still has enough color to land well in the right context.