Princess Eugenie, Princess Beatrice, Zara Tindall and Lady Louise Windsor have been tipped to “pick up the slack” to help Prince William and Princess Kate by a PR expert. The Princess of Wales has faced serious health concerns this year, beginning with major abdominal surgery in January. This saw Kate, 42, being hospitalised at The London Clinic for 13 days before returning home to Adelaide Cottage. The mother-of-three later announced she had begun a course of preventative chemotherapy after tests found that cancer was present. As a result, the princess has stepped back from public life until …