Gloucester Honeysuckle Tiara, and Princess Alexandra of Kent wore a pearl and diamond necklace as a tiara, a piece which is no longer in the family. It looks like The Princess Royal (Princess Mary, daughter of George V) was also in the group, though hard to see.
The second event from the video was a return banquet hosted by President Heuss at the German Embassy.
Queen Victoria's Crown Rubies, The Queen Mother also wore the Oriental Circlet Tiara. Princess Margaret gave us a beautiful view of Empress Marie Feodorovna's Sapphire Bandeau, which she paired with a diamond rivière. And The Duchess of Kent completed the visible tiara group with her Kent City of London Fringe Tiara. (Princess Alexandra, also present, had a brooch or something in her hair.)
But try as they might, no one could out-sparkle The Queen at the return dinner. Behold:
Satisfyingly sparkly, no? I can't decide whether the best part is the Dagmar Necklace or that sapphire bandeau...
Photos: via Getty Images as indicate, British Pathe video