Shows how inconsistent TG can be. I think that I only got the mattress
But I doubt about the duvet. A duvet (French word with many synonyms like eiderdown,..) is usually a (washable) double sheet closed on all sides except one. Through that side it is filled with a thick blanket made of feather or down. This is the kind of stuff you get on CX, AF, SQ and many airlines. The advantage is that you get the nice feeling of a clean sheet in cotton on your body and the lightweight and warmth of a down blanket.
On TG I only ever had a yellow, or purple or green slippery blanket in some artificial material. But that's not a duvet.