Single colour could suggest ZBS, and Zemek is only recorded as working for ZBS 1951-1954, with nothing shown in Masin's Zemek publication (posthumously) for NCVU in 1963, showing anything in this style, and nothing either in Raban's Modern Bohemian Glass of the same year. Is Machovska known to have worked for ZBS? As is becoming very obvious, there is often an overlap and similarity of designs between factories, and authorship is a particularly thorny issue. Klinger was a master in these very organic forms, though to suggest all ZBS items of the period were his designs would also be irresponsible.
Bryn, would you please put up a link to the web-site you mentioned?
Thanks,
M