Cat flaps?
I presume a few people have cat flaps in current operation.
What sort of dimension is the aperture that is available when the flap is 'open'.
Is 6" square the right sort of size for a cut that isn't huge, etc?
I have a plan to make a panel to fit into the space when the sliding patio door is a few inches ajar and have it 'reasonably closed' as the winter arrives, but still allowing some access. I can then even bolt the door in position, when necessary. The flap would be free-to-use, but nobody else has tried to enter the premises via the wide open door all through the summer, so it should be OK. I've been able to leave the door six inches open for the last while, but the weather is closing in...
There is no requirement to chip cats here and she's not keen on collars and stuff, I've only ever seen one once, some years ago, so there can't be much of a 'selective security enhancement' on the access arrangements.
To pre-empt those who would complain of the lack of a picture with this post, this is her now, under the table as I type this, taking advantage of the fact that I declined the item that I was offered for my tea.
View attachment 15904
(Picture blurred for purposes of protecting the squeamish)