Can anyone recommend a cat flap to fit a 12mm thick wendy house?

Hi all,

Just put up a new wendy house in the garden and am putting a wooden run next to it so my buns can have 24/7 outside access. I've seen lots of people use cat flaps so bought a brown Petsafe one and tried to fit it at the weekend. I was really proud of myself for working out how to use a jigsaw and cutting the hole by myself but when I went to fit the cat flap the 'tunnel' bit was too short so left exposed wood and a dangerous gap for bunny feet to get trapped in.

I've since bought the white version of the cat flap which said it has a tunnel fitted but that one is nearly two inches long so I would need to get a hacksaw out to cut it down!

Surely someone has found a catflap to fit a wendy house or shed with 12mm thick wood without having to cut bits off?

Any help would be greatly appreciated!

i used the dogmate dog flap in my playhouses.it came with 4 strips of thin plastic(cut it easily with scissors)that slotted inside covering the edges of the hole.