Jacob is nearly 2 isn't he? George never self settled until he was 2 and that was only because we pushed him into it. We had just gone along assuming he'd learn to settle himself in his own time. But when I was 8 months pregnant with Milly I was shocked to realise that we were spending up to 4 hours each night trying to get George to sleep. No wonder I felt so exhausted all the time. So we made the decision to train him.

We didn't want to ignore him or shut him in his room etc so we used the technique of putting him to bed, allowing him to either settle or come out, and just putting him straight back every time he left his room, with a few quiet words ("back to bed, sleep time now"). The first night was difficult (he came out 163 times before he went to sleep!) However by the end of a week he was happily going to sleep by himself and has done so ever since (he's now 3). We put him down at 7 and he stays in bed until we give him permission to come out at around 6am. The other things that helped were a regular routine starting about an hour and a half before bedtime, and letting him have some small choices (eg which soft toy he wants to sleep with, which story he'd like to have).

So no, it wasn't a "magic" age-related thing, but it was something that worked, with no crying or distress, so you might like to consider it. But you'd need to move Jacob into a bed rather than the cot, because as you say you don't want him injuring himself.