The problem only occurs when the clutch is released, previously it was mainly when holding the car on the clutch for very short periods, or when on an incline, but now it's all the time.
Even pulling away from traffic lights, roundabouts, the 'knocking' and some slight vibration through the clutch pedal can be felt, passengers can also hear the knocking.
Dealer says because problem only occurs when clutch is released it cannot be the gearbox, has to be clutch/flywheel.
Driving the car everyday is no pleasure anymore, totally fed up with it.