If I were the owner of your list, I would delete the
user:
 
      David de la Hunty <[log in to unmask]>
 
who does not VRFY at the principle MX host:
 
   punt-1.mail.demon.net
 
nor do the other two MX hosts seem to maintain SMTP sessions.
 
As best that I can tell from your info, that account (mail
system) is effectively looping.  Thank goodness you have
a moderated list, otherwise, you'd be pulling your hair out
trying to stem the flow, and the co-requisite on-list whining
that invariable follows. ;-)
 
--  co-owner:   INFOSYS, TQM-L, CPARK-L, ERAPPA-L, JANITORS, LDBASE-L, et -L
URL:mailto:[log in to unmask] "Never confuse the messenger with the message"