Trying to add John Gardner author.

I am trying to add a person to the site, the person I am trying to add it the author John Gardner:

en.wikipedia.org/wiki/John_Gardner_(British_writer)

But Listal tells me I can't because there is already a 'John Gardner':

www.listal.com/john-gardner_iv

The one above, already on Listal, is not the same person, and has James Bond book incorrectly attached to his page. The John Gardner that I am trying to add is the James Bond continuation author.

When I click on the 'View all John Gardner books' tab (on either John Gardner IV or John Gardner VIII , I am taken to a blank page. But the 5 books that appear in the 'Books' section of John Gardner VIII are correct.

Looking at the images, I think John Gardner IV and John Gardner VII might be the same person.