Lou, what about Stirling Moss winning the Argentinian Grand Prix, Trintignant at Monaco in 1958, 2 more GPs for Moss in 1959, all in Coopers, and further wins by Moss, like
Monaco 1960, incidentally the first GP win for a Lotus, Moss again at US GP, Monaco and Nurburgring, etc., etc. All for Rob Walker.
Seppi's win wasn't Walker's first, but I think it might have been his last.