Sparklefizz
^has she any curtains left hanging?^
My vet, whose cat had had 7 kittens, said she went home at lunchtime to feed them and check on them and they were nowhere to be found. Eventually she found all 7 kittens hanging on her curtains like bats!!!!!!! 
Many years ago we had two young kittens, left to sleep in a cosy bed in the kitchen. Came down in the morning, they were nowhere to be seen, but one of the kitchen drawers was mysteriously open. Kittens had managed to get into the drawer, somehow climbed over the inside end of it, and had presumably slept at the bottom of the cabinet. Thank goodness, once I called, they managed to get themselves out again!