I'm going to tentatively date this to between the wars, on the basis that I've seen that star pattern used on other glass from the 1920s, so you may have to push ownership in your family back one more generation. Where were they living circa 1930? The reason I ask is that I collect Manchester glass, and a surprising amount of it offered on eBay is from the local area, more than you would expect statistically, even long after the relevant glassworks closed down, so if it was bought within reasonable distance of a local major glassworks, that could be a clue.