https://yamcode.com/fitting-ca....t-flap-in-upvc-door-
https://zenwriting.net/chiefpr....int5/cat-flap-instal
Installing a cat flap onto the door will allow your pet to come or go when it wants. Follow these steps to learn how to mark out the shape, then use a jigsaw or hole saw to cut it and install your cat flap. If your cat flap is equipped with a Manual 4-Way lock, you can block access to wild animals or pests, as well as strays. It's also an excellent idea to have some pots of plants around for your cat to hide in. Placement A cat flap is not only a way for yo