I am not sure I can be of too much help. Both my children are shocking sleepers. But I did have a thought about why your little one may be lying there awake. With my DD I do lie with her to go to sleep. If she isn't exhusted she will just lie there and be anxious about when it is I am going to leave, so kind of just keeps herself awake to make sure I wont leave. I have found a good way to counter this is wait awhile to she is relaxed, tell her that in 2 minutes mummy has to go, but will come back and check on her. Then when the two minutes is up, I say to her, ok 2 minutes is up, mummy is going and will come back in 2 minutes to check on you. Then go back and check on her, even if I think she is asleep I whisper I came back. If she waits then I repeat the process. Doesn't always work, but most of the time it does.