Hi. I'm not sure if your sleep prob has resolved itself but my daughter suffers from chronic insomnia. We use melatonin to get her to sleep but she used to wake every night around 1-2 am and stay awake for 3-5 hours. A few months back i started giving her liquid magnesium and now give it to her daily and her waking at night has settled immensely. We went from a sleep through every couple of weeks to sleeping through most nights. Getting to sleep is still a prob and hopefully I'll be able to ween her off the melatonin once the sleeping through is sorted. The nights she does wake (and the nights she can't settle despite the melatonin) I find her vibrating rocker helps her get to sleep. We also have vibrating pillow that I use if the rocker's batteries are out.
The other thing I'd suggest looking at are ferritin levels with ablood test. Both my girls (and I) suffer restless legs so I give iron supplements to us all.
Lucia