Looks good to me At the moment I dont think we need to mention feral cats  I doubt that it is common for feral cats to enter a house via a cat flap On the whole cats are uncomfortable with entering anothers territory although I imagine it does happen occaisionally especially if a feral cat learns that there might find food inside If someone can find a useful reference on the subject we could readd it Mind you I did once find a wood pigeon tapping at my girlfriends cat flap  which seemed particularly unwise