 In his 2007 autobiography, Mower states that he believed for years that his year of birth was 1940, but later he discovered that his birth was not registered and he was born on 12 September 1938.Several reference books on film and television, including "Who's Who On the Screen" (1983) and "Who's Who on Television" (1996), give his town of birth as Pontypridd, South Wales, instead of Oxford.In 2007, he took part in the BBC Wales programme "Coming Home" about his Welsh family history.