Kynan used to be like that - quite happy to fall asleep in my arms or on the breast but the minute I tried to put him down in his cot he'd wake up and cry. He spent quite some months having most of his day sleeps in the sling but now he's just started going back to sleeping in his cot for his day sleeps. However he now needs to be wrapped & rocked to sleep and I have a very gentle procedure worked out for putting him in his cot. It doesn't worry me though as it all obviously makes him feel safe & secure, only takes a few minutes, and I imagine with time he'll need less help going to sleep. So yes, perhaps Tamsin will grow out of it (hopefully LOL).