He was definitely there. He is mentioned as a guest in Hello! article about Princess Beatrice's birthday.
And although some of Beatrice's friends were no doubt disappointed her cousins William and Harry couldn't make it along, they took comfort in the fact Monaco's royal hearth-throb Andrea Casiraghi was on hand to set hearts aflutter.
Queen Elizabeth: "I cannot lead you into battle, I do not give you laws or administer justice but I can do something else, I can give you my heart and my devotion to these old islands and to all the peoples of our brotherhood of nations." God, Save The Queen!