Okay, so I am awake at 5.30, which I'm not best pleased about, BUT

DD slept through from 7.30pm til 5am! Woohoo - it's working! Now if I can just get her to sleep in a little later again then better still, but baby steps...
ETA - after my previous post but before she started going all night without milk (2 nights ago) the wake-up had gradually crept back to 6.45, so I'm feeling hopeful