I am thinking sleep regression too. You know Annabel has been fairly inclined to long NWs since forever, but we haven't had them for a good while and now they are back! Nothing obvious I can see as to why. She's healthy, has a mouthful of teeth, good routine etc. The last few nights she's been up for 3hrs. Zzz. Same as T, she's not overly upset on her own and doesn't seem as though she needs us in the room, she just won't settle for aaaages. Sorry not to have any actual suggestions, but here with you in sympathy. My approach atm is to leave her to it as much as possible and hope she goes back to sleeping better! The only way through it is through it kind of thing.