Just wanted to say, if you have a cat flap, check it isn't frozen shut as mine was tonight.
My lovely girl was trapped outside and thankfully okay but wouldn't have been if outside all night. I think it was condensation on the 'fluffy' insulator bit running around the cat flap freezing it shut.
I've wiped it down but shut her in for the night, we're now on the bed about to go to sleep 