So sorry if I mis-led you, the reference book I used only referred to joint names post-1970, but the other, more informed board members are right, they did a lot of collaboration right back to the 19thC. Having looked a lot closer at your pics, which I should have done in the first place

, I can see that they are indeed much earlier than the '70s, and the plain look of the piece and unusual backstamp give a few clues as to the possible age. The elephant was often used as a symbol of the strength of the British Empire, and it remained in use during at least the 1st quarter of the 20thC. The very simple, almost austere style would suggest that this piece was made during a period when we had a need for utilitarian ceramics but overtly decorated pieces would seem garish or distasteful, and this, along with the clear message of 'Strength and Reliability', could very easily point towards a time when we were at war, possibly 1914-18.