K Series 1.8 Engine Knocking Noise

I have recently bought a 2001 freelander with about 60k on the clock! From day one after a few mins of getting warm a knocking noise start to come from the engine bay at idle but cant be heared under revs. It has been into th garage for repairs and the head replaced...still the problem occurs and also has also been back for new cams as the garage thought the cams and original head had picked up some fash which had worn the guides in the head and cams. They are obviously not finding the problem do you guys have any ideas my partner is giving me hell...........

Many thanks Dan

Can you give us some more description of the noise, rev range, stationary, in gear etc

You cant really hear while in gear or driving the vehicle but the rev range for the noise is between 750 to 1100 and then it dissappears. Its a quite loud knocking noise easily heard inside the cabin of the car. The knocking increases in speed as you rev until it dissappears as mentioed above. Seems to be coming from top of engine. The car runs fine.........
Regards
Dan

Im not sure?

Have you checked carbon purge valve?

Inlet manifold pressure?

ignition timing? The 2001 should be MEMS 3 ECU, it might just need a remap/software download as a last resort