Is to put him to bed at 10pm. 
A couple of late nights due to being at a wedding and then a birthday party in the last few days have proved the only way to stop him waking at 5am is if he doesn't sleep until 10pm the night before.
And I was hoping moving bedtime from 7pm to 7.30pm would do the trick!
I can't have him up that late every day, it would drive me mad! I need my evenings for watching grown up tv, studying and the occasional bit of adult time with dh!