I have a pair I bought in the winter sale after Christmas. I love them but do beware and take each boot style on its own merits - read reviews and email questions; they're very helpful. Some boots seem to be high quality, others have issues that turn up in reviews. I wish I had asked them about the shoe sizing as I bought a 39 that feels like a 40 - at least! (I've fixed it with an insole, but will ask more questions in future!)
Lilli from http://frocksandfroufrou.com/ has bought a few pairs (where I heard about Duo) so might be worth searching her posts.
I actually have average sized calves but there's nothing like wearing boots that hug your calf perfectly, which is why I will shop at Duo again!
Also they arrived in a couple of days... to Australia.