I do not remember seeing Pr. Irene of Greece at that event. I remember that HM Queen Anne-Marie did not attend because she was in the last days of her pregnancy, few days later in fact she gave birth to Prince Philippos of Greece. A big disappointment of that visit was that Queen Sofia, who apparently was not yet in possession of her second grand tiara, the Cartier diamonds and pearls tiara, had to attend both the official evening at Buckingham Palace and the second one at the Spanish Embassy, wearing the Ansorena fleur-de-lys tiara. She had already worn the Mellerio waves pearls and briolettes diamonds tiara at the formal ceremony with the Lord Mayor. Then, the Infantas Elena and Cristina, who also attended the Spanish Embassy evening, wore respectively the Franco floral diamonds tiara and the Empire diamond tiara, today mostly worn by Princess Letizia. Of course there was still the Niarchos rubies & diamonds parure as a diadem to be worn, not to say anything about borrowing the Countess of Barcelona's tiara, in those years used mainly by the Infanta Maria Pilar, or Princess Irene little circle diamond tiara. It's very rare that a Queen is obliged to wear twice in a row the same tiara during a state visit. Mind you, it is not a critic to Queen Sofia, I think this decision was made just to keep her low profile, that it is often her trademark, and that's why we all love the Queen of Spain. : : : :