I am currently working my way through a vast number of crystal glasses, and have just completed an exercise to try and find images of all Stuart crystal patterns named on the replacements website, where there are no images available. I suspect that the references such as STU9 are internal pattern names, so if there is no image available on the site it is not possible to find an image elsewhere. This is a shame as, for example, STU9 is described as "fan and crisis-cross" which matches, at least by description, the pattern on Paul's glasses.
I thought if I posted the names of the patterns I have been unable to find images of, other GMB members might have examples and they could post pictures. The ones I cannot find anywhere are :
English (very difficult to search for due to Stuart being English crystal!)
Albemarle
Ranelagh
Griffin Park (lots of images of my old football ground!)
Lucerne
Warfield
Paul, I did check your glass against all the images I was able to find, that were not available on the replacements site, but it wasn't one of them. I do agree that it strongly resembles Diana pattern, and my first thought was that there may have been a plain foot version. However, the stems on yours are quite distinctive and definitely not the same as the Diana wine glass stem. Maybe we will get lucky and yours is one of the patterns listed here.