https://world-news.wiki/wiki/U....sing_a_Cat_Flap_in_B
Professionals should handle the installation of a cat flap onto your door panel. The doors are typically made of a thin plastic exterior that is bonded to an insulation-enhancing, soft polystyrene base. It isn't easy to cut through these materials. It is much simpler to fit the cat flap into an existing glass pane or to have the hole drilled for a new door. A Glazier can do this for you. Easy to fit Upvc door panels are an excellent option if you have a cat that you would like to let it in and out of your home with no hassle