Royal Doulton Bunnykin Bowl

Hello,

I purchased this Bunnykins bowl but I'm unsure of its age. The web states that after a period of time, the manufacturer started to category the items by alphabets. How can you determine the category when no letters are visible? Since no date is listed, does anyone know when this bowl was made? I have several Bunnykin items, some with copyright dates but are these dates the real date of manufacture?

Thank you.