Screen switches off when lying on my back reading?

[SoxmisUK]

Ok I have no idea why but upon waking up this morning My HTC One has started behaving differently. I have a couple of newspaper apps and when I lay on my back to read them from underneath the phone screen turns off.

Ultimate rotation Control will not enable and I tried un-installing it, trying it again, then re-installing it and the problem is not fixed. The problem exists without Ultimate Rotation Control even installed so I suspect a setting somewhere?

Any app or screen when viewed whilst lying on my back (Screen facing down..) causes the phone screen to switch off.

Frustrated. Cannot find a setting to get it to behave normally. Can anyone help please?

 

[SoxmisUK]

Can anyone help? I'm thinking about a system reset but would really prefer to avoid it..

 

[SoxmisUK]

I removed an app that I had installed a long while (Gravity..) and this it seems was causing the behaviour.

Problem fixed.