I've seen a couple of Sherdley ads from a Woolies promotional magazine, dated 1938 and 1940. Most of the glass pictured is what I assume to be pressed glass in very traditional pseudo-cut patterns, with a few more utilitarian items like lemon squeezers.
The earliest I've seen Nordic advertised is 1948 - and David just sent me a press release from 1961 which refers to it still being in production.
Not sure that adds anything in terms of your original query, Anne. But I thought I'd share the info anyway...
The Woolies Museum site is fascinating - definitely worth a browse. And run by a really lovely guy from their IT department in his spare time.