He's been in a Grobag since he was tiny, but he's almost two now, and I don't want to buy enormous 18mo + grobags and want to get him settled with a duvet.
I've been settling him for his nap with a duvet for about a week and he's been fine, last night tried him for night time and he screamed the house down. Put him in his Grobag and he calmed down a bit, but it was only when we moved the duvet out of the room that he finally went to sleep.
He was a terrible sleeper until 16 months, but since then he's been excellent, and I don't want to rock the boat.
Try with a blanket inside the duvet cover first, it will lay flatter - he may be frightened of it fluffing up and thinking he'll be smothered. Then when he's used to that, you can swap the blanket for the duvet, keeping the same cover.