An interesting comparison, I think, is Henry Greener's 'Beaconsfield' commemorative sugar & creamer RD 325547 of 31 August 1878.
In addition to the specific Beaconsfield commemorative decoration, these also have the shamrock, thistle and rose embossed decoration, and the overall shape and style of the pieces is very similar to those shown in the opening posts.
The date of the Beaconsfield design registration also correlates well with the 1st lion trademark ( although the Beaconsfield pieces only bear the registry date lozenge).
Fred.