King Charles has been told to “slow down” with his public engagements by Queen Camilla, a source has claimed, as he gears up for a hectic summer – as well as a round-the-world tour to Australia. With the King still undergoing treatment for his cancer, Buckingham Palace had confirmed earlier this year that his summer programme would be reeled in to allow for a stronger recovery. And the Palace has previously indicated that Charles’s doctors have been “very encouraged” and “sufficiently pleased” about the King’s progress. But regardless of his recovery, the King has weathered a busy slate of eng…