I have two cats as well as Bella, but Bella is pint-sized and can fit through a catflap.
When we moved to the house we were going to put a catflap in the porch door at the back but then had second thoughts - Bella's on her own for 4.5 hours a day so I'd be worried about her being stolen, having some freak accident (she's not exactly lucky that way!) or just annoying the neighbours by barking her head off at the various cats that sit on the back fence. So as a compromise we have a catflap from the kitchen into the porch and all 3 animals go and hang out in the porch where they can watch what is going on.
Lately Bella has decided she can only fit through the catflap when she is on her own, or, more truthfully, that one should not have to squeeze ungracefully through a catflap when one's owners are there to come and open the door in the manner fitting for a princess. She'll stand there with her Minnie the Moocher face on, looking at you through the catflap, refusing to come in herself - it can be 10mins, it can be 20mins, but oh no, Bella is NOT coming through the catflap. We actually thought maybe she had grown a bit so we did a test - we sat in the living room (other end of the house) when we knew she was waiting to come in through the back door, and then I shouted "Bella SQUIRREL!!!!", and whaddya know, she was miraculously able to fit through and came haring into the living room going "where? where?!!!".
We know she can fit through it when she wants as we leave things in the porch for her to chew when we're out and she goes and gets them and brings them through the catflap into the kitchen (sometimes I'm amazed what she manages to fit through there, these big bulky boxes!), she's just pure princess!
