Wow, silk duvet. Not seen them before. I'll go and investigate further. £61 though - is that the norm for a decent duvet? TBH I can't remember the last time I had to buy a decent one as out last couple of kingsize were given to us by DH's grandad (new unused for some reason).
I have a silk duvet and love it. It is really lightwieght. Only problem is they are not really washable so would be reluctant to have one for a child in case they are sick in bed etc. I use sheets and a cotton blanket topped with a wool blanket for my children as I think it is easier to regulate their temperature that way, but I am told that makes me v old fashioned. Some of the children's bedding companies also do cotton duvets. The other advantage of wool and silk is that they are naturally dustmite repellant.