I have the Wedgwood booklet, and it is a very nice piece of art / story. The stamp in question is on the last full page (reproduced in part below). Of all of the pages, this one is not the prettiest, due to the rate table rather than other interesting information. On this page, we have 3 versions of the 1/2 p with 2 bands (left and right). The 2 1/2p and the lower right example of the 1/2 p have only the phosphor on the left side. As has been mentioned, the stamp itself can be badly trimmed.