Our 1 year old little man has tea with his big sis at around 5pm (well it starts then but takes a while for him to eat, plus yoghurt and fruit for dessert), then he goes to bed around 6.15.

He often only has 1 sleep during the day now

I find if we go out then he's very tired by bedtime and he usually has a good nights sleep too.

I'd definitely try and give her some extra stimulation and see if that gets her sleeping better! I tend to try anything!!