That's a handy and comprehensive guide, Paul. Thanks.
I have just had the 4.31 software update and unfortunately, this has broken the guide navigation when using a profile other than the shared profile which still works normally. Annoyingly any button press or voice command takes the guide to the final item in the profile list rather than the desired channel. This is on both my 360 boxes so I believe it must be a bug. A new guide feature has been introduced in 4.31 which must be the cause of the bug. Restarting the box(es) does not fix it. I think it will take another update before this is cured.