Bedtime breakdown

After a year and three-quarters of relative tranquillity (give or take the odd early, early morning irruption), this past week Kimberley has been waking up in the middle of the night and being very clingy. Yesterday evening she wouldn't even sleep at her normal time (or at all). I finally got her to not burst into tears when I left the room after reading five books to her and filling her cot with more (to read by the landing light) but she was still making noises at midnight when I drifted off. Then at 2.45am she cranks up her routine again, taking an hour or something to calm her and doze off between Altaa and myself. Then at 7.30am, she's bright, alert and active, when her parents are anything but. Does this child not need sleep!