"To satisfy a night-time test you must need either of the following:
help with personal care at least twice a night, or once a night for at least 20 minutes someone to check on you at least twice a night, or once a night for at least 20 minutes, to make sure that you are safe For this benefit, night usually starts just after your household has gone to bed and ends just before your household gets up in the morning."
I'm sure someone more knowledgable will be as to advice better though. I would imagine that they would argue early waking isn't out of the norm for a child.
When we renewed DS2's DLA at 5, we were told that it's not abnormal at that age. And it's certainly not unusual to expect to have to et up with a typical 5yo
When we renewed at 8, we got HRC without a quibble. A typical 8yo who routinely gets up at that time would be able to grab a drink, go to the loo and entertain themselves safely, while DS2 has a big wet nappy that needs seeing to and climbs all over the kitchen in search of food and enrages his brother (older, but really needs more sleep than he does to function, but can't get to sleep until he's settled) by turning the lights on.
There's been nights when my own insomnia's kept me awake until 3 or 4am then DH has been up with DS2 an hour later!