Hi TrickyWoo56 and

to the Club !
For your screen issue "john348" is probably correct,
but did you describe the issue correctly ?
When you say, "When
stationary the screen drops ....."
It should NOT do that when you first come to a stop !
The Screen
should drop down to the lowest point after switching off
the Ignition, and when the Ignition is switched back on, it should then return
to the position it was at immediately before switching off.
Your Dealer can reset the upper and lower limit points,
or you may be interested in an after market product such as :
DealerTool which can perform this,
and many other useful Maintenance Tasks / Test Procedures.
Regarding the "noise" when the volume is turned down,
there is a possibility that this is not coming from the audio system at all,
but from the Glove Box Locking solenoid, which can emit a sort of high frequency "hum" !
Put your ear near the locking button to see if that is the source of the noise !
If you only hear the noise with the Ignition off, and it is a sort of high pitched
but much quieter version of a wonky emergency services vehicle siren (

),
then it could be the fuel system bleeding excess pressure from the fuel rail back into the tank.
Cheers

