I just read through the AVR600's manual. It does allow HDMI2 output to serve a second zone, but it does so by slaving the second zone to the main zone - it has to use the same input. It was also interesting to see that Arcam's manual specifically recommends against using HDMI2 for the second zone, advising instead that you should use analog video due to the complexity of using HDMI for the second zone.