After all your good advice we managed to get Tilly to sleep to a more reasonable hour but I'm back for more help! Ever since the clocks went back we've got the opposite issue. She now barks half an hour-hour after we go up, something she hasn't consistently done since March. We come down to settle her but sometimes this takes 2-3 goes. When you go in sometimes it seems she doesn't know you're there, she does because she stops barking, but she just stands there blankly for a few seconds. She's also started coming into the living room in the evening, she hasn't done this for quite a while as she hated the memory foam bed I bought her for in the living room. She'll pace around trying to sleep somewhere, often trying to curl up against things are that aren't comfortable! She will use her bed once she's wandered around realising nothing else is as good and particularly as I've added a topper to it. I wonder if a night light where she sleeps will help for when we go to bed.