Then there was one. I would have guessed that was going to be the most difficult on the quiz (but then I'm often surprised by how quickly the hard ones go).
Lison! I was getting annoyed by that one, since there is enough evidence it was on the way to Cherbourg. I just "rechecked" Lison, being sure I'd already done it as the most obvious place to change on a direct cross-country route from Perpignan (in the sense of avoiding Paris). I must have assumed that you would not have doubled back via Caen - but then again, why wouldn't you?