To show, a 2-handled butter dish and cover in purple marbled glass, the underside of the dish bearing the Sowerby peacock trademark and an indistinct registry date lozenge (1X - Y?-W- X /XX). (Permission for the re-use of these images on the GMB granted by Trevor Cornforth).
The dish and cover is (are?) Sowerby pattern 1414, shown (as a registered design) on page 7 of Sowerby pattern book XI (1885).
Oddly, the dish (or perhaps a somewhat shallower and elongated version), without the cover, is shown (also as a registered design) simply as a 'dish', Sowerby pattern number 1413, on page 37 of the same pattern book.
I think there are two reasonable candidates for the registry date lozenge:
10 - Y - W - 9, 10 March 1879 - Parcel 9, Sowerby RDs 333167-333173
17 - Y - W- 11, 17 March 1879 - Parcel 11, Sowerby RDs 333424-429.
Does anyone have either a 1414 butter dish and cover or a 1413 dish with a clear registry date lozenge to help in determining the correct Sowerby RD number associated with the pattern (or, indeed, patterns, if 1414 and 1413 are from different registered designs), please?
Fred.