jazzandh - good point about whether she's waking up grizzly or happy... should definitely help point to whether they are being woken up for some reason, or whether they are just finished sleeping.
Dd2 was def a grizzly sort, so was easier to see she needed more sleep, just couldn't get it without help for some reason (probably her sodding teeth, everything was her sodding teeth... so the slightest bit of light sleep, hunger etc and she'd be up. That's why a biscuit helped, and Calpol occasionally helped, and going back to sleep on me helped etc).
If it was just finished sleeping time, then that's when strategies like groclock/other visual 'zits still nighttime' cues might help. But tbh, with dd1, the groclock didn't help until nearer age 4, and only then because my mum was staying in the lounge for a few weeks, so she knew it would be big trouble if she woke her up before 7.
Re her 'routine' - sounds like a late tea and bed, especially if she's been up since 5? We would always have lunch 12.30/1, sleep 1-2hrs, snack 3, tea 5/5.30, then bath and bed with milk and biscuit all done by 7. Even if up at 5, theyd still have to wait till 7am for brekkie (but milk earlier if course). If you bring forward tea you might be ble to get another snack in before bed!