I don't know how contrived it is, but there used to be a "Frog and Nightgown" on the Dover road in South London. We used to point it out to the children, if they were still awake, driving from the Ostend ferry on visits home.
I heard the derivation of the "Goat and Compasses" was "God Encompasseth Us", but it sounded a bit of a stretch.
In North-West London (?Harrow) there was "The Case Is Altered". I heard it used to be a brothel, run by an Italian (or Spaniard), known to the clientele (also mainly Latin) as "Casa Saltera" - roughly "the joint is jumping".
It's nice to find someone else who knows what a merkin is. I always got strange looks in cinemas laughing at the President's name in Dr. Strangelove; even with the giveaway surname of Muffley, very few people get it.