The vase is unmarked but is by Gray-Stan glass. (glass, stem shape, trailing, colour and shape are all correct for Gray-Stan and I'm 100% sure it is Gray-Stan. My large vase by Gray-Stan is also unmarked.)
Shape comparison can be seen in a colour plate 179 on page 93 of 20th Century British Glass Charles Hajdamach front left hand footed bowl.
I've never seen another.