Has anyone contacted Brooklands, Donnigton Park or MotorSport Magazine? Also, considering his high profile pre-war, the Frazer Nash and BMW enthusiasts clubs or the Le Mans experts may know where to look.
You probably already know this, but are you aware of the collection of his papers at IWM?
http://www.iwm.org.uk/collections/it...ect/1030007556
HTH,
Bruce