Thanks M and Christine for taking a look and for the above links, much appreciated. This certainly appears to be a difficult subject area to research.
The bubbles are tricky to capture accurately, however, I think picture 2 above, is the closest representation. The bubbles' sizes and shapes do vary, but as a generalisation tend to be tall and thin. The vase also has a very slight textured feel from the bubbles inside the vase.
Thanks for the comment on the bubble size for Walsh Pompeian, after looking through quite a few examples of Pompeian I was struggling to find an accurate match for the bubble size/shape. I did also have a good look over the base for any indication of a Walsh mark, however, can't see one, although I do appreciate that the absence of a Walsh mark may not also be conclusive.
I'll keep digging and have also have a look into S&W and of course any additional thoughts/insights are most welcome.
Thanks,
Greg