I had a look at the blog and must admit it looks very pretty, but I can't really understand the point of it. I mean you have to wear something underneath anyway, so why bother with the skirt. Maybe in very cold conditions it's for extra warmth? The only thing that interested me was the fact that it might keep the horse's back warm (I wonder if you can wear a smart one for hunting?) but, as Newforest says, the wind would be a problem. I can't imagine many days in this country when you could wear one and look as elegant as that, a lot of the time you'd be trying to stop it flapping all over.
Gorgeous ponies and interesting tack though