@RabC
No idea as I don't know what you actually did, and even then probably don't have the knowledge base to understand. What I will do is explain my actions.
I firstly went to Amazon and got the authors page for these guys - just put in 'Bird and May books'. This put up the page with list of books.
I did not pick up any book, I just copied the URL from the top of the page i.e.
www.Amazon etc
Then opened a new post/reply, clicked on the link icon and dropped the URL into the link box.
And hey presto! It magically appears as a link to the author page.
Hope this helps. If you did something similar then I am stumped!