Princess Kate’s outing is hanging in the balance as the Royal Family prepares for an appearance. The Princess of Wales usually presents the trophy to the winners of the Wimbledon men’s singles and women’s singles events every summer. In March, Kate announced that she had begun a course of preventative chemotherapy following her abdominal surgery two months before. The princess briefly returned to the public eye on June 15 when she attended Trooping the Colour alongside her children, Prince George, 10, Princess Charlotte, nine, and Prince Louis, six. Kensington Palace was keen to stress the pri…