Hi Paul, good question. When ever I've seen this particular design its is nearly always referred to as 'Crystalex/Bor Glassworks' with both names being referenced. I'm not sure of the exact history between the two, however, always thought they were basically the same, or at the very least strongly entwined.
This particular design is shown on page 34 of Mark Hills book, in the form of a vase, however, I gather this specific design was produced in a number of different forms, the ashtray being one.