As far as I know, all pre-war Alfa matters in the UK are taken care of by the Vintage Sports Car Club (
www.vscc.co.uk). They might have their own archives or they could probably forward any requests for information to some of their members, some of whom are probably old enough to have actually been around when these cars when new ... You might also write to Bill Boddy, the veteran journalist, care of Motor Sport magazine (
www.haymarketgroup.com), who has been reporting on pre-war cars and their history for at least the past seventy years.
Alex.