Microsoft update status shows Lumia Denim available for Switzerland since yesterday, but my L930 didn't find the update until now.
If you use P4D switch it off in the app and try again.
I just unticked the "enable preview for developers" option and it's now downloading an update. Let's hope this is it!
I flashed the new firmware rather than doing an OTA update and don't have the rotation problem. If you have the time, try doing a factory reset which wipes all your data - during setup the phone will download all your apps and settings and set up your homeecreen, so no hassle, just a couple of hours while it does its stuff. Maybe that will sort it out.