Steering knocking

[drbsheffield]

I was just wondering if anyone has an idea what is wrong with the car? I have a w209 CLK and there is a knocking noise from the steering when going over bumps and if rocking the steering wheel, it is no great drama as the car is under warranty, just wondering if anyone knows what it will be before I get around to taking it in. I had the bushes replaced recently but the noise is still there.