Thanks Nev / Anne, I just got these photos of the base from my dad, they all look to have a pretty similar base stamp, so I think it’s highly likely “ Helen Louise” is unregistered Greener @ Co. My pictures also include Davidson’s Brideshead which is a registered design with the number on the item RD 130641 TO 130643, 8/13/1889 BRIDESHEAD and the plates have a star pattern. The Greener pieces are also known as “ Bridesmaids” but are unmarked.
What do you think? Cheers Mike