I have a horrible rattle noise from the front of the engine on my TD5. It does not follow engine revs and may get less with higher revs. The harmonic damper has been changed but I was surprised at the play in it. A little transversely and about 3-5mm longitudinally with a knocking sound, measured against the crankshaft pulley. Is this amount of play ok or are there any other ideas?

The front torsional vibration damper thingy is rubber bonded and if the rubber bonding fails it rattles back and forth, it should have no loose movement. If it fails catastrophically it can damage the radiator.

It was the damper. The mechanic had bought both the crankshaft pulley and the damper and fixed them without checking that the damper was properly bolted tight to the pulley. So it was loose. All fixed now and he is unlikely to do it again.