Thanks for your reply Reiver. I'm not sure it's the clutch, however as you can see in the YouTube video I'm rocking the car back and forth when it's parked and in 1st gear. Therefore I don't think is surge or hunting as you mention. I could be wrong though
As long as there is tension on the drivetrain everything is smooth. On flat ground coasting along in first or second however, it will start jerking back and fourth without any change in engine pitch. It's as if the mass of the car tries to overtake the drive train/wheels and bounces back, then the opposite happens and the motion become amplified until I stop it using one of the before mentioned techniques. Brake, accelerate or depress clutch.