Royal Wedding Style: The Mystery of Lady Sarah Chatto

Easily the second best dressed person at the Royal Wedding on Friday was Lady Sarah Chatto, daughter of  Princess Margaret. The real bugger is that there are absolutely no pictures of her AT ALL. I have scoured the online interwebs for hours and come up with absolutely nothing. Except some other wise folks also looking for pics and bemoaning the lack of them. The best I can do is this grainy TV still of her hat. So now I need your help, please.
Let me start by telling you about her outfit. It was slate grey. It was a slash neck and fitted, 50s style, into the waist in a clean line. It had 3/4 sleeves. It was belted at the waist with the same fabric and it had a flared a-line skirt. It was a study in minimalist elegance. And I gasped and grabbed my sister's arm when I saw it. She said, "stunning." We just breathed for a few seconds. And then she was gone, never to be seen again.
If anyone finds a photo of Lady Sarah Chatto from the wedding of William and Catherine on Friday 29th April 2011, please return it to me. And I will publish it for all to see and appreciate. Thank you.

UPDATE: Detective Nicky Rush from King James found this equally blurry, but far more useful image on the left. You can just start to see how lovely the dress is. Any advances?
UPDATE 2: the image on the right of the full loveliness courtesy of twitter followers @TalyaGoldberg and @aneeqaismail. Thanks detectives!