On Thursday I went to the V&A to see the Grace Kelly exhibition. After spending an hour admiring Grace’s style, we exited to the main costume exhibition. One dress made us all gasp. For there, in all its glory, was the Princess Diana ‘Elvis’ dress, the stunning off white gem encrusted strapless dress, with short sleeved jacket with the upturned collar. This was the dress that the Franklin Mint had donated to the museum in 2005/6, the dress that had raised the most money when Diana had held her famous dress Auction.  The dress was instantly recogniseable to all, one of Diana’s most famous, most successful looks. And yet its…