LONDON (Reuters) – Prince William has told well-wishers that walking behind his grandmother’s coffin had been challenging and had brought back memories, alluding to the day 25 years earlier when, as a boy, he followed his mother’s casket on the way to her funeral. William, the heir to the throne, walked behind his father King Charles and side by side with his younger brother Prince Harry during Wednesday’s solemn procession taking the late Queen Elizabeth from Buckingham Palace to Westminster Hall. “The walk yesterday was challenging,” William told members of the public who were sympathising w…