Hey Paul,
What’s with all of the forum spam you are getting? I think maybe it’s time to invest in some better forum software that can help to combat all of the spam you are getting 
Forum Spam
I find deleting all accounts that have 0 posts is also a good way to help reduce spam. A lot of times accounts will be created on multiple forums and lay dormant until enough have been collected then either sold off to a spammer or fed into a spam bot. Deleting those accounts that have never posted really helps combat that. Specially if the forums is fully visible without being logged in, there is no reason to have inactive zero post accounts.
Ive deleted all those that have no posts and have a website setup in their profile, but I think just deleting all with no posts may upset some genuine users.
I need to update the forum software, I did try some time ago and it went wrong, but just need to be brave and try again !
Well the spam problem resurfaced today so I have had to take the more draconian approach and delete all users who have not posted, apologies to any genuine users.
I think it’s worth it, the spam seems to be crazy recently!