I believe it's a genuine name. Which led to some confusion!
Unfortunately the photo of the base is out of focus, I do believe it's there, I just can't see what the writing looks like, which might have helped a little. All 3 of my bits are dated too.
The Chartres piece is not irridesent, but I have two others which are, a red goblet with a big blue moon and a small bottle with a spotted paisley shawl effect
The goblet was made in '83 at the London Glass Works, and is a bit "in keeping" with the style of your vase. It is marked LGW, and we know he went there for a bit to do some glass work at that time. The Chartres is dated '90, the paisley shawl bottle '89.
I did a bit of a web search, it brought me back here.
https://www.glassmessages.com/index.php/topic,23595.0.htmlThere are several threads about Norman Stuart Clarke; I've done a search of the board for you below.
https://www.glassmessages.com/index.php?action=search2