\nI have two cats, brothers from the same litter.\n\nBoth really affectionate. They never fight each other or other cats.\n\nOne goes in and out of the cat flap and has a wander as he pleases.\n\nThe other will not use the cat flap. Will go in the garden but never over the fence. Will only go outside if the back door is open. \n\nHow can I train him to stop using the love tree tray.