King Juan Carlos and Queen Sofia, accompanied by the Duques de Lugo, left for London yesterday to attend the 75th birthday of cellist Mstislav Rostropovich. Last night, they were due to attend a concert and a dinner at Buckingham Palace in honour of the musician. The Spanish royal family are holidaying on the island, and on Monday evening attended a concert at the Cathedral. Prince Felipe, heir to the throne, is also here, taking part in the Princess Sofia regatta.