We happen to have a duvet for the very cold nights, but have not used it once this season. In general we are always roasting and so opted for a soft flannel blanket. Lightweight, super easy to care for, and just enough warmth. Might be another option for you.
Actually I also use wool blanket for most of the year. But I had some trouble finding one to buy. Bought mine from Jelmoli some years ago on 50% off.
Generally, Jelmoli and Globus have woolen blankets but usually sizing is weird, i.e. not suitable to my needs.
If it is not too far away for you, two shops in Foxtown (Lugano/Mendrisio) (at least used to) have quite a selection of blankets.
I saw them in Jelmoli.
But no idea how warm they are...
I've read reviews suggesting that the silk duvets are heavier and less warm than down duvets. Also, if you're going to wash them, the silk duvets are very heavy.
You know, you can actually write more than one sentence in a post...
Anyway, wool is the new silk. So my wife says.