At some point when able to, we will be moving and our son will having a double bed. He’ll be about 2 and a half and I’m wondering about what to do about a duvet. I believe 2 is about the age you introduce one. Is it safer to give him a cotbed/ single size duvet or would it be ok to give him a double? Also what tog would be appropriate, I've seen a lot of the cot bed sized ones are 4.5. Thanks :)