What to do with a child who wakes up at 5 no matter what time she goes to bed?

[TooTiredtoGoogle]

DD has always been an early riser. Doesn't really bother us because she has one of these gro-clocks with a sun and moon, so she's been trained not to disturb us until 7am.
BUT, I think it's having an effect on her. She doesn't nap unless she's in the car, so by the time it's 5pm she really is the worse for wear so I usually rush to get her to bed for 6.30pm.
Would love her to sleep from 7-7. Have tried adjusting to later bedtime, but it just doesn't work for her. No matter what time she goes to bed, she always wakes at 5am!
Any ideas what I can do?
BTW - DD is 4.

Woke at 4am this morning. Can anyone help?

Is anything happening at 5am? DS's bed was next door to our neighbpur's alarm clock. Took us a while to work out!

Is she at school yet? If not, that might tire her out enough to sleep longer?

Yes, I would sleep in her room and see what happens at 5 am, could it be the sun coing in or the boiler or a neighbour leaving for work?. I recently slept in DS's room as we had guests and discovered why he has been waking at 6.30am lately- he had set a alarm for that time every day so he can get up and do his hair (he is only 8 ). Does she wake at 5 am even in the winter? I recemtly got a black out blind for DD (6 months) and it is giving us an hour or two extra in bed each morning.

Do you take her to the toilet in the night?
If not, I'd give it a go - perhaps 1am, get her up quickly for a pee and straight back to bed.

Thanks for all your responses.
DD still wears a nappy to bed, so can't be a toilet issue.
And there's nothing which wakes her because I'm often awake at that time (lying in bed, not making a sound) and there aren't any noises from neighbours/boilers, etc.
We also have blackout curtains, so it can't be the light.

She's been like this since the age of 2 and I always thought she'd grow out of it, but it doesn't look that way now.
Any other thoughts? Or. success stories on combatting early rising?