They have a clear.net.nz email address. They use Clear ADSL in their home office and use an XT connection when out of the office. The problem is sending on port 25 to smtp.clear.net.nz (yes, using SMTP AUTH) appears to get blocked on XT.
I've currently given them a work-around with another provider running on port 465, but is there an alternative port for smtp.clear.net.nz that anyone is aware of?