I've probably left this late and they will be sold out by now, but can anyone recommend a really warm duvet to make it easier to keep the heating off this winter? Not wool, because we've had carpet beetles in the past, but we don't have any allergies, so it can be synthetic or feathers/down. I need two, one fairly cheap (under £50) for a student dc who isn't here often, the other one is for me, so I don't mind paying more! Both double size.