It has just had the prop shaft done about 2 months ago so that is all okay

It sounds like the click is coming from the area of the high pressure pump in the engine bay. There are no leaks and the clicking only occurs when you put the car under pressure at all other times it is responsive and drives well.

IRD?

The noise is very metallic in origin and seems to come from the front left side of the engine.

Yes, thats right you can rev the engine without the click and you only get it when you first start off under pressure.

The clicking (as opposed to a knock) only happens when under load and other than that it runs perfect.

Hello I have a problem with my Land rover that I am trying to fix. It makes a clicking noise under pressure and then you have lots of grey smoke emitted. I have done a video to show you what happens. (Youtube link below) Any help would be appreciated.