When I was a kid in the West Riding of you know where, we called the passageway between two houses a snicket. In Yorkshire dialect books I've seen the same thing called a ginnel (maybe S.Yorks?. Now that I'm in Kent no-one knows what a snicket is, but they refer to it as a twitten (god knows where that originated!) It occurs to me that there must be a few more variations to describe an alleyway around parts I have not visited, like East Anglia and most of the rest of the world. Any offers??