William A. Coates (1919-1993) was a technician and lecture assistant at the Royal Institution (1948-1986) . He was awarded the Bragg Medal in 1975 [2,3]. Coates was born in the East End of London on 7th November 1919. He went to Shoreditch Grammar School. He became an apprentice at the Exchange Telegraph Company in 1934 .
He joined the services in 1939 as a Private. He later joined the parachute regiment and was involved in Normandy Landings. He left with the rank of Captain . Coates worked as a technical assistant at Charing Cross Medical School before Eric Rideal recruited him to work at the Royal Institution. 
Initially, he worked with x-ray diffractometers as part of David Phillip team. In the 1950s, Coates became involved with lecture demonstrations working particularly closely William Lawrence Bragg  Coates was also involved in producing several Open University foundation courses 
After his retirement he remained as part time consultant at both the Royal Institution and at Imperial College London. Coates died 7th October 1993.
Coates actually has a Wikipedia page with a bit more information than I have here.
- William Albert Coates (1919-1993), Retrieved 2018-11-24.
- Institute of Physics, Bragg medal recipients, Retrieved 2018-11-24.
- Obituary: William Coates, The Independent, Retrieved 2018-11-24.
- The Legacy of Sir Lawrence Bragg : selections and reflections. Thomas, J. M. (John Meurig), Phillips, D. (David). Northwood, Middlesex: Science Reviews Ltd. 1990.
- Science course unit 7 – Open University Digital Archive, Retrieved 2018-11-25.