Does this shape appear in other series? No - (none recorded in image database) although there is some similarity to Later Series 505.
Nicholnack art in pottery
This is very similar to the shape currently catalogued as Early Series 451 although that is taller (23cm). Only a single example is recorded for both 451 and 457, and in each case the incised number is slightly unclear. Perhaps they are actually the same number, notwithstanding the size difference, either 451 or 457. More examples are needed to resolve the question. A similar un-numbered piece is recorded with an intermediate height of 19 cm (below).