Hi Laura, it looks to me like their a time in the mornings is fairly short and longer before bedtime. And I think even 8:30 is probably too early for the first nap. I started off with it at 9, and it's only now, with the first nap not before 9:30, that I think I'm starting to see improvement in her ew. So if you said 6 am is get out of bed time, then 3h a time, first nap is 9 am. I'm not sure how much sleep h and j need, but Medi doesn't need much and if I let her sleep 1.5 h in the morning she'd be awake tomorrow at 4:30. The afternoon one can be a bit longer, hopefully if they have a shorter sleep in the morning, they'll be more tired by the afternoon. But - What time is your afternoon school run? Something tells me it's 3 pm. Am I right? Because really, to get to bt at 6:30-7, they should be napping till 3 or 3:30. I'm very lucky, dh will sit by the baby monitor for ten minutes while I fetch Enfys from school so Medi can have her nap. I don't know if that's possible.
Anyway. I'm rambling on now

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This is roughly how our days go
Wu 6-6:30 (I don't get her up till 6, just the last few days she's started sleeping till 6:30)
Nap 9:30-10:30 if she ew, 10-10:45 if not
Nap 1:45-3:30
Bt 7
We're down to one nf now (hurrah!); anytime from 2-3:30.
Does that help at all?