"Hallett of High Holborn" Chess Set, 19th Century

This pattern of chess set is, for some reason, associated with William Hallett of High Holborn, early Victorian London. However, I have yet to see any evidence that definitively associates these sets with Hallett. This style is indeed English and 19th century, and rare, but that is as far as I can conjecture. If the set was made by William Hallett, then it would be dated to the 2nd quarter of the 19th century.