I had this exact same problem. The dealer replaced the nuckle joint on the steering column and this improved the issue but did not solve it. The issue was then diagnosed as worn gear and bushes in the steering rack. The worn bushes were easily seen when removing the rubber boots as steering fluid had leaked out through the bushes and filled the boots.
The steering rack was replaced and now there is no clicking/knocking at all when making big or small movements to the steering wheel. The front end feels really taught and quiet and makes the car feel new again