In message , at 12:37:40 on Fri, 8
Jan 2016, Robin9 remarked:

If this group is not moderated, then why and how do some
threads disappear? Also why, if I haven't posted for some time,
does a message appear, encouraging me to contribute?


You need to ask whoever runs "Londonbanter" because all they are doing
is mirroring the newsgroup uk.transport.london, which has none of the
attributes you mention.
--
Roland Perry