That's taken from C C Jenkin's book on Cockers so it's not an official extended standard, just the author's take on what the standard means. I have that book - think it's the only Australian book on Cockers. It's called "The Cocker Spaniel" by C C Jenkins, published privately by the author in the 80's, not sure if you can still buy it but I've done a quick Google search and the Cocker Club of Victoria have it for sale at $30.
Jane