see my comments elsewhere on Pete's Reg. Pierce vase. Could be wrong, but a link between Pierce's more up-market wave/marine type designs - whilst he was with Stuart from 1937 to 1939 - and the retailer Stonier may presently be unsubstantiated. Plenty of Stuart utility type glass does have that connection of course - i.e. those with the -S-, but possibly not Pierce's designs.
Broadfield House Glass Museum might be able to help - they did communicate with Pierce around 1999, and so might have more information for you. Speak to them.
What sort of designs Pierce was producing whilst employed with Stonier in the early 1930's, I'm not sure - perhaps some are shown in C.H., but I don't know. ......... must have a look.
As for Stuart designs in general, am I correct in thinking that we have discussed previously here that Mervyn Gulliver either published or in some way had a connection with producing a detailed resume of Stuart patterns/designs? Could be wrong, but it rings a bell - the only problem is that I think it was a very limited publication, and doubtless very difficult to source in the ordinary way.
Could be that this would contain more information on Pierce designs.