EUREKA! I looked at your drawing and something was familiar....the notched top especially. I walked away and the image was imprinted on my mind. Then it hit me! It's SOWERBY.
I rushed to the catalogues and confirmed - it is definitely Sowerby 2477 vase. Sizes made were 5", 6" and 8". Colours were flint, amber, blue and green. Your drawing, Tony, is a 100% identical match.
For anyone with our Sowerby catalogue CDs it is in Catalogue 38 circa 1950s (possibly 1956) on the second CD.