Hi Donnamum,
On the advice of our consultant I never allow my girls to go to bed under 5.6. It also depends when they last had a bolus of fast acing insulin, if it was within 2 hrs of bedtime I would be even more cautious and check them during the night too. They are both on pumps, so have no long acting insulin to complicate things. When my little one was on Levemir she could easily drop 10 mmols during the course of the night, it was a real worry. So I guess you need to know how your daughter's levels behave at night, by getting up to test her as often as you need to. It's tiring, but the only way to do it, imo.
Sue