Gearbox Noise/Whine/Whistle? See video!

Hey all,

I have a MY09 Subaru Forester with a 5 speed gearbox.

There is a high pitched whistle/whine coming from what I think is the gearbox. The noise goes away when I press on the clutch pedal a little, doesn't require the pedal to anywhere near all the way for it too stop making the noise.

I have recently replaced the throw out bearing, clutch disc, pressure plate and pilot bearing.

Any ideas on what it could be?

As you can see in the video the noise goes away when I am pressing the clutch pedal down but goes away when I lift off.

https://youtu.be/TKLlq1oBLY0

EDIT: Just to put a resolution to this. It was a worn out input shaft snout (Where the throw out bearing rides on). A sleeve kit has resolved the noise.