New knocking noise on a TD4

Hi guys, my Freelander 1 has just starting making a knocking noise. It seems to happen at the end of the steering range on a hard lock either direction. It had an oil change 2 weeks ago and has been ok until now. The noise sounds like it is coming from the engine but is hard to tell where. The alternator belt is also squeaking and this started at the same time. But looks tight enough. Can anyone please advise me on some ideas? Thank you.

Look at the auxiliary belt tensioner, but are you sure it's not your CV joints.
Mike

...also the main crank pulley - they delaminate and need replacing - shine a torch at it and see if there are any metallic flakes floating around - if there are, it will need replacing.

have you put all the bolts back in the under protector?