A few days ago I started getting "undo typing" notifications every few seconds when typing and "undo delete" notifications when deleting emails, even though I wasn't shaking the phone at all. I disabled this and thought nothing more of it. A day later I open Safari and it immediately turns 90 degrees anticlockwise into landscape mode and stays there. So does every app that will open in landscape. Nothing I do will make the screen rotate into any other position so I have to lock rotation to keep the phone in portrait mode. I also find that the compass doesn't work (can't calibrate it) and any app that uses augmented reality (FlightRadar 24, Sky Safari etc) won't work either when I point the phone up at the sky. In addition, the phone is going through the battery at the rate of 10%, per hour on standby and if I dare to use it it gets quite warm and uses 20% an hour or more. The phone is 2 weeks out of warranty and I'm not in a position to take it to a Genius Bar until January as I'm working abroad. I reckon I have a dead sensor, at the very least. Any other suggestions, please?