Hello, I hope the following assists you.
As the clutch is hydraulic there is no adjustment available. If as you say the clutch is operated through the input shaft then it is usually a concern with the small lever that pushes on the release bearing, the lever usually cracks allowing it to skip on the splines when the clutch pedal is pressed.
If this is the case then the lever can be replaced without having to remove the gearbox, remove the plug on the end of the gearbox, remove the pivot shaft from the small lever and pull the lever out.
I hope this helps.