Dating a WSL Dinner Plate

Hello everyone! I'm a new collector of WSL china, and have this wonderful 9" dinner plate. While the piece does not have a date of manufacture on the reverse, it does have several unique marks that I am unable to identify, even after extensive research. Are they significant or simply imperfections in the manufacturing process?

I am hopeful that this page can help me decipher these mysterious marks! Thanks to all in advance!

WSL Plate 1.jpg

WSL Plate 8.jpg

WSL Plate 9.jpg