Not a designer in the sense of the total aircraft, but John Wilson became the chief flight operations designer at Hatfield after a test flying career which included the DH 108, 110, Vampire, Comet (co pilot on the first flight), and Trident.
John was involved with the Trident autoland and flight deck systems design, then very active with the flight deck / aircraft systems in the HS 125 and BAe 146 aircraft; and I suspect with some significant advice on Concorde and Airbus designs via Bristol and Weybridge.