The air intake pipe that goes from the side air inlet vent via the air filter and then bend downwards towards the bottom of the engine. It then (well on my disco 3 anyway) it just literally rests over the other tube it connect to. Is this correct or is it supposed to be clipped on ??

I'm getting about 26.5 mile per gallon TDV6 !!!

Yes they just push over the lower pipe.

Thank you