E320CDI Knocking noise
First time poster, so be gentle please

I've just bought a 2000 w210 e320cdi and I'm chuffed to bits with it. It has recently gone through an MOT with no advisories. However, recently it has developed a knock when I turn right under power. This only seems to happen at 30 mph+ and only when I apply right hand lock. It's quite a pronounced knock, but irregular.... Any ideas ?
Thanks,
Andy


