Took the mount out last night. There was some passing scattered cloud, but not enough to cause any issues. I got pretty much the same results as before - no real change - and couldn't establish a polar alignment with the iPolar. I had checked most carefully to ensure that everything was aligned properly.
Further e-mails to iOptron have brought the information that if the celestial pole is too near the edge of the field of view of the camera, this may also cause issues. I can guarantee that it wasn't near the edge this time.
(bangs head on desk in frustration)
