I am intrigued by the orders worn. The Queen Mother is wearing her Garter on her left arm. Therefore the sash is not the Garter. I wonder what it is. The occasion should shed light on this.
Edit: the Legion d'Honneur, of course, for the French occasion.
Quite possibly she is wearing one or two family orders at her left shoulder. And Garter star on left breast. Not convinced it is an ears of wheat brooch - could be a Garter bar holding the sash. Her necklaces appear to be Queen Victoria's (now named the Coronation) and her own coronation necklace. I should know the name of the central brooch. Of course the tiara is the Oriental.