This is the final presentation of the Blossom design, it is essentially the same as pattern 4517, (extremely rare), except with snow glaze rather than the “off blue” glaze. The pattern book records that it was sold at the British Industries Fair, (in 1936), with an incorrect pattern number.
This is one of the hardest to find of the ranked patterns. It was probably expensive to produce requiring all the detailed decoration to be done by a tube-liner with two colours of slip clay. This is the same technique used for her salad bowls and platters made for the USA market, but with much more pattern content.