Nigel is true.
Fabriacted in Železnobrodské sklo (ŽBS) - Železný Brod is town in northern Bohemia near to Turnov, Jablonec, Liberec.....
Must not be old becouse these pieces has been fabricated also after the velvet revolution in Czechoslovakia. So might be Czecoslovakia but rather Czech republic glass.
I am working on getting ZBS catalogues now. Be patient please.
Bezt reg from Czech rep.
Jindrich