Yes, Charmion, they have both come inside. Sam the Skull belts in and hoovers up any of SmokeyPokey's leavings. And little Binky has crept into the study through the conservatory and rolled about ecstatically on the carpet. She has an extremely loud purr.
But I hesitate to encourage this. Their owners might not like it, and also, I found a flea on Sam the Skull last week. I wonder if Binky has worms, as she eats constantly and cries for more. My husband calls her Oliver Twist!
Smokey seems physically in quite good shape, and rather likes the other two visitors. I saw Sam and Smokey eating together from the same dish last week. He lifts his tail and wiggles it (welcome gesture) to Binky. So no animosity.