I was getting breakfast in the kitchen and bent down to pet polish only to realise 20 seconds later that the cat I was petting wasn't polish, just looked like her.
I called the OH down and pointed out the happy purring interloper. He says"That explains it." Explains what? Apparently this cat had bounded into the sitting room and hoped up on couch with OH, he just thought it was Polish, but acting a bit odd. Therefore it explained the odd behaviour, it wasn't Polish.
Anyway cat continued to be petted, went back upstairs and snuggled on couch and basically made itself at home.
Now after about half an hour of pondering this odd behaviour it came to us...we used to have cat called Willow Boo. About 5 years ago Boo stopped coming home, when we got Fizzy and she started having kittens.
Turns out Willow Boo decided to come home. Hence the wandering in and making herself at home, as though she'd not been AWOL for 5 years.
A month and a half down the line and she's still here.