Missing plugs etc

Hi all, just looking around the engine bay today and thought I would check the turbo rod to see if it was seized as my LR is so slow but found that there was a plastic pipe where I thought it would be? I may be looking in completely the wrong place as this is my first TD5 or maybe the previous owner has tried to do something with it. Also noticed several plugs unplugged one of which on air box. I have attached some pics if anyone can advise.

Many thanks

Is the three-pin socket in the air box for the AAP sensor (first photo attached)? If so there is no plug for it as the only plug near it is four pin? Is the AAP required and if so, why would someone disconnect it?

the pipe in pic 2 is for the waste gate actuator, it should go from the actuator to the inlet