We managed to catch her within an hour luckily, but it was quite tricky...
I have no idea how she managed to escape- it's quite amazing when you think about it!
She somehow managed to use her claws to slide open the grid at the top, then she somehow managed to get down from the cage to the floor, then under the sofa.
There is a picture of her 'Escape Route' below.
I was really worried when I discovered she was missing, but even when I found her I was so worried that she might have hurt herself by getting down... She must have fallen at least in part of her journey.. Luckily when we managed to capture her she seemed completely unharmed and was running about in her cage afterwards with ease... phew!
We actually found her really quickly, but it was catching her that was so hard! It took us a long time to finally capture her, as we couldn't move the sofa in case we squished her, and she wasn't really tempted by the food we left near the sofa.
We have added a little clip to the back of the cage now so that she won't be able to escape again! (I hope!)