Allow Mock locations. And annoying "hold" on calls every time phone put up to my ear.

I have a galaxy s6.
SM-G920I to be exact
Running marshmellow
I have enabled developer options
I can not find the option allow mock locations at all.
It used to be there before the update.
I have tried resetting the device.
It seems the option has completely vanished.
Is there any way to bring the option back?
The only mock location option is the option to select a single app.
So have they done away with the option. And just included the option to select a single app?

Ps I'm sure the mock location option was there on my old s6.( Identical model and carrier also software version was also Marshmellow same build)

Also

Is there any way to reduce the touch sensitivity on this device. I know there is on the s5.

Every time I call and put the phone upto my ear it places the call on hold. Very embarrassing.

I'm deaf in my left ear so I need to use my right ear..
But every time I do. My ear touches the hold button.

I've tried searching for an app that replaces the in call screen. I've tried apps that "reduce sensitivity" there must be something I can do? Even move the hold button?

I don't want to root my phone as its only a month old.
I'd only root if I can guarantee the Knox counter won't trip.

I'm aware the hold issue is very common however have not been able to find a resolution.

Any help would be appreciated.
I have searched Google for answers but can't find anything.

Thanks