What you'll need to get him to do is visit here
http://whatsmyuseragent.com/ and get him to post you the entire contents of the box that says "Your UserAgent" and then see if any part of that string matches any of your blocked bots, post back and i'll take a look
P.S can you edit your last post and remove all those bots and add an attachment of a text file? that way folk don't have to scroll for ages to read the thread