John was the second son of Charles Frederick and Caroline (nee Dawes) Postle. He was born in Ashwell, Hertfordshire on 24 April 1893 but lived in Buntingford, Hertfordshire and was educated at Buntingford School.
Frank was born in Ashwell, Hertfordshire on 11 October 1898, the fourth son of David and Clara (nee Kirbyshire) Potton of 42 Station Rd, Ashwell, Hertfordshire. He was a pupil at the Merchant Taylors School in Ashwell