I think it's amazing - very 'smart' in the truest sense, and an honestly unusual take on padded jackets. I also think you should get a Dryrobe, though, or something from an outdoor specialist.
I love the idea of wearing central heating, @IHaveAlwaysLivedintheCastle, but £550 is a bit of a jump from £150!
OP, I used to do this when I was young and, frankly, idiotic: I felt I had to be well-presented and attractive all the time, which led to my turning up to outdoor race meetings and the like in outfits that would be suitable for a day shopping the January sales but NOT standing around a wet field for hours! I'm quite sure I caused a fair amount of mirth among the well-wrapped and waterproofed regulars. Don't be that woman 🙂