I've just ordered one, cracking deal. They also have a double, 13.5 tog at £29.95.
These feel so much nicer than synthetic ones!
Description from site:
Goose Feather And Down Duvet/Quilt, 10.5 Tog, Super King Size
Premium Quality Spring / Autumn duvet is filled with 95% Goose feather and 5% natural Goose down. Finished in a 100% Cotton cambric feather-proof cover, with a square cassette / box construction to ensuring that the feathers stay in place while the cloth walls eradicate cold spots. The feathers help to added weight to the duvet so that it lightly moulds itself to the body to keep you warm and snug all night long.
233 Thread Count Cotton cover finish, for comfort, breathability and also makes it suitable for people who suffer from house dust allergies.
While the feather and down has been specially chosen for it's high thermal qualities, all our natural duvets contain fillings that have been washed, sterilised and steam purified to the European Feather & Down Associations highest standards making them hypoallergenic.
* Size: Super King, W260cm x L220cm (Suitable for W180cm x L200cm Super King Bed)
* Colour: White
* Material: 100% Cotton, Filling: 95% Goose Feather / 5% Goose Down (550gsm)
* Washing Instructions: Professional Laundering, Wet Clean only at 40°C
* Brand: Linens Limited