According to Charles Hajdamach 20th Century British Glass page 109, after a description of Caerleon range which 'they described as 'flint base', 'orange blue and yellow splashes pulled streaky and iridised' (Plate 215)' he says
'Many variations followed including a 'blue and brown rock effect on light amethyst bubbly' glass and 'blue Caerleon with an applied snake'.
Mine looks like those he pictures on page 110 but there isn't a single hint of orange and yellow splashes

Also mine is full of bubbles but yet 'bubbles' doesn't appear in that description.
I've spent all afternoon trying to photograph mine to get that level of iridescence and surface texture from it and I can't.
I do think yours is a Stevens and Williams Caerleon vase but I wonder if it is one of the other variations ? Or whether yours is the range as described above and mine is one of the other variations?
Also I wonder if these were free blown rather than mould blown, and that some of them are kind of one-off shapes?