Sorry about the raft of spam messages over the last few days. We're working to eliminate this.
If anyone has any previous experience of eliminating spam on a Discourse platform, please get in touch!
OK, I've stopped the site accepting new user registrations, at least to stem the flow of annoying spam. Will have another look at the settings to see what we can do to turn new user registrations back on again.
You can contact us at firstname.lastname@example.org with specifics.