Jomor,
i totally understand the anger. got a neighbour who feed homless cat's....you all can imagine the smell around the house.
i even got this far that i found out how much it will cost to get ride of them with the help of proffessional.....and saveing money now for that purpose
Best practice so far - besides a gun/mad dog and horn (which actually works quite well) is anti cat smell or something like that. Go to the local pet shop and ask some sort of parfume that cats dislike. spread it all over the bella and their gone.
hope it helps,
T.