If the noise disappears when the clutch is pressed , it wont be the release bearing, as stated by the second garage, it will be gearbox related. More than likely will be an input shaft bearing, but could be any number of bearings within the box.
When you press the clutch, it stops the input shaft and clutch disc contacting the clutch cover and DMF, but obviously takes time to stop spinning completely, hence the sound of it slowing down. Could try a gearbox Oil change and see if it improves anything.
When you press the clutch, it stops the input shaft and clutch disc contacting the clutch cover and DMF, but obviously takes time to stop spinning completely, hence the sound of it slowing down. Could try a gearbox Oil change and see if it improves anything.