Yes! And we have provided a recess for this purpose. Please measure your chosen catflap carefully.
The dimensions are:
Dimensions of the recess around the opening: 21.5cm (H) x 19cm (W)
Dimensions of the opening: 20cm (H) x 18cm (W)
One of our customers recommends this catflap as a good fit: https://www.amazon.co.uk/dp/B001UKX484
Please note we have not verified this.
We send a card with every Kitty Cabin that has the dimensions printed on it in case you want to take it to a pet store.