Nice to meet someone else who shares my addiction! As a collector I'm keen to ferret out anything obscure, and the Stratford service is obscure, while the rest of Stuart's production is fairly well known, so I restrict my collecting to plain pieces. They also tend (at least in New Zealand) to be found in the bric-a-brac shops so are good buying at $5-$10 (between 3 and 6 pounds).
Funny you should mention Woodchester, the only piece that breaks my rule is a blue bowl which has been decorated in the Woodchester pattern. Clear glass was definitely used for Stratford, I've posted some photos of my collection which include clear glass, and I have a copy of the Andy McConnell's book and have also studied that illustration of the catalogue extensively - my wish is to one day get at least a full sized version of that illustration but I don't know where to start going about inquiries (that said I'm on the message board now so that should help!).
I've figured out how to downsize my photos so here's some shots of my collection - I definitely have the smaller clear version of your vase, and have seen several examples of the larger green one here. I can't be 100% sure but I think Stratford made its way to New Zealand with immigrants rather than through importers, so seldom do they turn up - decorated Stuart was definitely imported in quantity.