Well DD2 seems to think sleep is over rated!!

In bed at 7pm up at 11:30pm, 2am, 4am until 5am, then 7am.
After 10mths of this I think I may need some assistance in locating my brain!
I'm a zombie!
Is this her routine every night?

Maybe you could try shifting her bed time 2-3 hours later to coincide with your own bedtime, so that you can take advantage of her 4.5 hour stretch? An added bonus is the 4-5am wake period would actually be at a more reasonable hour (more like 7 - 8am), so you'd get an 8 hour period with 2 wakings, instead of 3-4. To get her going to bed later, start her bedtime routine 10-15 mins later each night, until she's going to sleep at the time that suits.