https://trade-britanica.trade/....wiki/Get_a_UPVC_Door
Cat flaps allow your pet to move around whenever they want, without you needing to let them in or out. They also help prevent your cat from toileting inside the house. Installing a cat flap into the door panel made of upvc is a lot easier than a glass door, but it does require some skills and the proper tools. Take a measurement of the door Fitting a cat door in a front door could be difficult however, provided that the cat flap is the correct one and you follow the instructions it shouldn't be too difficult.