When the friendly people at Isabella Oliver - a brand about which I know pitifully little - sent me some photos from the look book, I had a moment of deja vu. In fact, I emailed back to find out if this dress:
was a variant of this one I'd seen on Cate recently from Kate's blog (photo courtesy of Make Do Style):
Turns out that Cate's dress is vintage Ossie Clark - something I realized when I went back to MDS and re-read the post.
It's like dress twins, yes? Strikes me that, if you love the billowy look and you don't have access to vintage royalty, this might just be your alternative.