Mr Jones (The Sittaford Mystery)

In the novel The Sittaford Mystery, Mr Jones is a commercial traveller. He is staying at The Three Crowns in Exhampton.

He is mentioned in the novel, but never seen.

This is the first Jones in the Christie canon. It sounds like the kind of name she might have commonly assigned, for example, to tradesmen, just like Gladys for domestic staff. Surprisingly, there are only three Mr Jones.