I have been watching the phone a little more closely over the past few days and I think the Access Point thing may be a red herring!
Every now and then, the phone is rebooting for no apparent reason. Upon boot-up, I do get asked to confirm Access Point (which according to Nokia Live Chat, should not happen. If I reboot the phone myself, I get asked to confirm on boot-up so something is up with this).
Anyway, I thought some program was setting my volume low all of the time, but now I see after the phone has crash/rebooted the volume is set to 14 or 15.
I think the next step is to stop all programs from running in the background to see if that cures the periodic crash/reboot unless anyone has any ideas as to how I can see any crash/dump reports from Windows Phone 8?