kmexpert on "[Plugin: Wordfence Security] Usernames Discovered"

Thanks Guys,
for these suggestions. Mitch Powell, With one exception, all these accounts were set up to display very different nickmanems to the actual usernames which are full of upper and lower case characters, numbers and punctuation
I didn't know about the ?author=N, but Barnez I'd already activated the Wordfence option disabling it.
Since my post, I have had 536 emails notifying me that an IP address has been blocked.
I'm still hoping for some input from Wordfence's support people.
BWs
JAmes