izzy as you may know J is was at the end of the queue for sleepy dust. My girls also slept through very very early. From a baby who would only sleep with my boob in his mouth up until 12 weeks, he now sleeps in his cot in his room for manageable periods. He is 19 weeks old.
We do not have a proper bedtime routine as I cannot do everything, but watch his cues. He is going to bed earlier and earlier, and he is doing this himself. Tonight was 8pm which is fab. He will wake once or twice and I will get him up for the day at the latest at 7. I think the trick is to tackle it with the morning routine personally.
With naps he usually has 1.5 hours awake. And sleeps for 45 mins or twice that with a little swearing in the middle. During the week I may need to wake him for the school run in the afternoon and he copes ok. He naps on the morning run and I usually walk to the village or park with DD2.
He has all home sleeps in cot. He has learned bedroom is for sleep. In the day he sleeps with normal clothes and cotton cellular blanket. Night time with a gro bag, and you can see the relief on his fave when he is in pjs and has the bag put on. I do that downstairs.
He has teddy light mobile for daytime naps if put down awake. He will swear at teddy, but teddy usually wins. At night, ewan strums away during feeds which are now mostly shorter than ewans piece.
How old is LO? I would probably go with the flow until about 18 weeks when the sleep regression should be fading.
Remember 4 months is 17 weeks not 16.