very impressive piece Keith - good find, and I agree a good design According to Benson and Hayhurst, Irene Stevens left Webb Corbett in 1957 although she remained a consultant until 1963, so I'm assuming this design was created some years prior to 1968, but not entirely sure.
Those outlined ovals are reminiscent of Kny's well known leaf motive, and which was copied again much later by John Luxton.
Surely this is going to bring 'that' shelf down