If the shape and size is consistent with a Chance diamond dish (9½ x 6 inches, 24 x 15cm), then a very strong candidate
Fantastic! This looks to be like the decoration from one of the variants shown in the photo on p58. Very rare and it shows that 'Cut Pearl' wasn't always a static design (if this item can be categorised as such).
Peter Knowles' dish (opposite page) is another such example that 'broke the rules'.
Great find :mrgreen: