This may sound strange, and I'm not sure where I got this idea...
Enfys was down to one feed at 5 am around 12 weeks and it was the same, she was hungry then but wouldn't be at 7 or even 8. She didn't take a whole lot at her dream feed either, so I just didn't give it to her for a couple of nights. She woke up hungry around 1 so I fed her and she had a whole feed. I went back to giving her dream feed after about three nights and she would sleep through then.