Is the slave piston pushing the clutch fork all the way forward?
Press the clutch in and use a board to keep the pedal down (pressed against the seat).
Go under the car and look at the clutch inspection hole----how far has the slave piston moved the clutch fork?
The back of the clutch fork should almost be touching the bell housing.
In Clarks picture, the clutch fork is relaxed---if the pedal is pressed in it moves forward.
Checking Clutch Disc Wear
John