Don't discount the Italians too quickly - there are all grades of quality from Italy
Good point Peter
I am sitting looking at a book with Murano glass lamps that are very similar to yours and the original posters c 1950s - 60s/70s
Vistosi - Lampada da tavolo (table lamp) several designed by E Capuzzi - simple coloured lamps lit with bulb from inside, very similar shapes.
Also made by Salviati and C Moretti (Moretti pics I have tend to be glass bases with shades)
I am sure there were many other makers
I used to think all the simple glass was usually Scandinavian but recent book buys have shown me a lot of vases and 'table sets' by Nason, Fratelli, Barovier, Salviati, and Vistosi were very simple.