Hi David, thank you for your advice. It took along time, because of my and their summer breaks.
First I got a mail from Barovier & Toso, that they doesn't belong to their production, they suggest the Seguso factory.
Vetria Artistica Archimede Seguso Slr. mailed me, that the chandeliers could be made in their factory. But they couldn't add anymore, because it needs a lot of time to look at the archives. So next time I visit Venice, I have a personel invitation to look at it !!
Although it's not sure that they are Seguso, I'm very, very happy with the results. I also bought some wall lights (bought them together), so they are maybe also Seguso's.
Kees