Thank you for showing this, Chris. I haven't seen an example before. Particularly nice in the uncommon clear opalescent glass.
The date lozenge is for 17 March 1879 - Parcel 11, which covers the RD bundle 333424 to 333429.
RD 333424 is actually Sowerby pattern 1414, a covered butter dish.
It would seem that this footed dish is Sowerby RD 333425 (and described as such in Cottle and Thompson) which corresponds to Sowerby pattern 1382 (shown on page 7 of Sowerby pattern book IX of 1882).
Fred.