Thanks, this is merely to canvass possible other prolific designers. Yesterday's original figure of 5000+ designs was based on knowledge of a career lasting from 1922-1958. We are now aware that the designer in question started designing glass for one company in 1912, ten years earlier than previously thought, and still contributed designs for several years (possibly 5) after their official retirement in 1958. This almost certainly means that figure has to be revised upward. Added to that, the designer had already designed glass for another company for eight years prior to that 46+ year stint, so the designer in question probably designed over the longest continuous period in 20th century European glass manufacturing history. Adam, you are right in the Czech connection. This designer designed all 320 items in one pattern, a feat that Frantisek Vizner alleges, no other designer, has ever matched, or indeed would be capable of doing. I have it on good authority, this designer worked alone, and that until the last three years before his retirement, no-one else worked in the design office.
I will reveal who the designer is, following further research and confirmations.