Hello Penny
Not seen that pattern before. I also have a similar small cased vase which I have been unable to attribute.
Mine also has a white inside, is about 4" tall and, I have only just noticed, a ground pontil.
Sorry about the picture but it is next to a Sowerby blown cased item for comparison.
Small Sowerby blown pieces are made differently, the blowing rod was attached at the top, after breaking off, the top is ground flat, so no pontil mark on the bottom. If there is a Sowerby, or registration mark it is usually on the bottom.
I have seen a couple like mine on Ebay in blue and green malachite.
There is a larger, similarly made piece in Cyril Manley's book, Decorative Victorian Glass (page 96 if you have it). He thought it might be Sowerby but was not sure.
It is possibly Sowerby but my guess would be one of the other glass houses trying to emulate Sowerby cased malachite glass, possibly Davidson.
So we still don't know

Mike