I found this link today. It is the collection of the Beaulieu Museum archives and there are many Sunbeam images to include the Venezia and the land speed record cars. They offer images for sale (and the price is a little steep) but you can look for free!
I viewed all the Venezia pictures. You know I even have the press releases in three languages, these marketing printed pictures stamped by Rootes marketing dept, and even one of the negatives. Those were once found by the Aston Martin Lagonda (1975) Limited people. Unbelievable how these things were spread around.