Heppell items belong to the lozenge period and presumably all items should carry the diamond Reg. details ............ I don't see this design in the Board's archive for the Heppell factory, so it will be worth asking the seller to confirm if the piece in the link carries a Reg. lozenge, and if so what the details are.
Alternatively, like other Heppell moulds, this one assuming it's theirs, may well appear in Davidson catalogues c. mid 1880s - it's possible that a connection has been made with Heppell based on the colour and similarity of shape to known Heppell designs.
According to the list of Registration designs for 1882, there were only three - Nos. 390584- 86 ............ as far as I know these cover the three sizes of upright fish vases (390586) ........ the butter dish and cover (390584) .............. and the unusual upright sugar bowl (390585). Images of all three pieces can be seen on the Board's archive.
Of course this might be an interesting item of Heppell's, - perhaps the seller can help us with this one.
