2 year old early morning waking

[jb07]

HI
Does anyone have any experience of 2.5year old waking at 4am (not always exactly same time, so cant be a noise outside etc), she rarely goes back to sleep but we just leave for up to an hour - she talks, sings and eventually shouts. This has gone on for over a year - we've tried milk (no help), she wont be soothed back to sleep, we've tried putting her to bed earlier and later - all to no effect. She goes to bed/asleep alone. Its very dark in her room.
She cant go to nursery for a full morning as she is too tired.
Any ideas? We've tried all the usual sleep consultants.
Thanks

[compo]

I would let her go to nursery for a full morning - then she might sleep better at night?