DS (4 years) wakes up every day between 5-5.30. He used to wake between 6-6.30 but this is the exception now. It's affecting his behaviour and attention in school. We are knackered. Tried everything: Gro clock didn't work. He has a rigid bedtime routine and goes to sleep at 7.30. Putting bedtime back or earlier doesn't work. Trying to keep him in his room doesn't work; he gets louder and more stroppy and wakes his baby sister. Any ideas please?