Squeal when reversing no brakes applied.

[Speckle]

Hi guys hope your all well. So recently I have discovered on my A5 2012 b8.5 1.8 tfsi. An audible noise coming from the car when I'm reversing. No brakes applied. It goes when I press the brake. And the sound is just like brake squeal. I had the disks and pads replaced all around 9 months ago. Strangely though I also hear a strange noise when I am on the motorway at higher speeds cruising. Another high pitch sound in a pulse like pattern. Since this has happened I have also been losing MPG quite a bit. Could anybody advise please. 

Ash