Any advice much appreciated. DS1 has always been a bit of an early riser and as long as he sleeps beyond 6 ish this seems to be enough and he is fine. But we are having episodes where he wakes earlier, at 5:15 ish and won't go back to sleep and he is absolutely shattered. When he was at preschool we could get through this using an occasional daytime nap but now he is at school it can't happen. He is pooped and coming out of school white with tiredness but then still wakes up the next day at 5:15.
We have had some success before with making him stay in his room until he goes back to sleep, but can't do this on schooldays and this morning he woke at 5:15 and is still up there now playing quietly. He's had a drink and some food and knows he can't come down until he's gone back to sleep. Usually this sorts it out and he'll then sleep later but today it's just not happening!