Thanks Mark, that didn't work out I'm afraid. This is what happened when I tried importing without deleting/recreating mailmandb:
I imported the datatase using a psql command in the database container, and then ran "manage.py migrate", which I think does the same thing as the Django admin command with argument "migrate" (?). It reports "No migrations to apply."
In the web interface the lists appear, but without any members, and as before when I the restart the core and web containers, they die after 15 seconds with the error messages as printed below.
(As I mentioned earlier, removing the newly minted mailmandb database and then creating a new blank one, and importing into that does work well (c.f. Stephen Turnbull's remarks above)).
Stephen
mailman-core | alembic.util.exc.CommandError: Version table 'alembic_version' has more than one head present; please use get_current_heads()
and
mailman-web | MAILMAN_ARCHIVER_FROM = (os.environ.get('MAILMAN_HOST_IP', gethostbyname(os.environ.get('MAILMAN_HOSTNAME', 'mailman-core'))),) mailman-web | socket.gaierror: [Errno -2] Name does not resolve