"The clear casing is in fact a pale flint colour" I find this phrase rather worrying on the Modernist site. What does it mean? Flint is clear, colourless glass!
Both pieces actually have slightly yellow clear glass (i.e., not good quality), which indicates to me probably Czech mid 20th century, as Dirk said Borocrystal seems likely. That these are so prevalent in the UK, also indicates Czechoslovakia rather than Murano to me; we must have had numerous tons of imports from the country and the glass industry in Murano is so much smaller