Cheers for the replies.
I'm pretty sure she's fit and healthy. I have a dog flap that she can use during the night, so I can confidently rule out the UTI. I might get her checked out for any health problems though to be on the safe side.
AlanT - lol, but I think you could be spot on! I've let her sleep upstairs these last few nights and she's been absolutely fine. However, my other half isn't happy and now I have another problem to deal with!
Seriously though, I'm equally concerned about her calming down generally too. I'm going to get her checked out at the vets for some peace of mind.
Thanks a lot,