I just wondered what time your children go to bed and get up for school during the week?
I have a DD in Yr 3 and a DS in Year 5. They are both in bed by 7.30. DS is an earlier riser and is always up by 6.30am, although he's often been up to use the toilet before that time. I have to wake DD at 7am. DS is always up early regardless of how late he goes to bed and is horrible when tired, same with DD although she will sleep late if she's up late. My ex has a real problem with their bedtimes and thinks they should be allowed to stay up until 8.30 - 9pm but I know they would be in terrible shape if this happened.