There are quite a few pubs around England called "The Man in the Moon" and I always thought this was just a... well, as good enough a name for a pub as any.
I have found in Brewer's Dictionary of Phrase and Fable:
Man in the moon. The nameless person at one time employed in elections to negotiate bribes. Thus the rumour was set flying among the electors that “the Man in the Moon had arrived.”
So I have passed a placid Monday morning speculating that this might be the origin of the pub name.
Well, there aren't any jobs to apply for that I can find, so I might as well have done this as gone back to bed.