According to Peerage News, he was the "second son of the late Major Frank James Wriothesley Seely (1901-1956), and a great-grandson of Sir Charles Seely, 1st Baronet. His mother was Vera Lilian Birkin (1903-1970), a friend of the future King Edward VIII, a daughter of British Colonel Charles Wilfred Birkin (1865-1932) (fourth son of a lace embroidery and tableware magnate of Nottingham, Sir Thomas Isaac Birkin 1831-1922). His aunt was Freda Dudley Ward (1894-1983), Marquesa de Casa Maury, a mistress of King Edward VIII (1894-1972) and wife of William Dudley Ward (1877-1946)".
