So do I fit part by part? Or put it together and then bodge it on?
Loosely fit the side vent pipe on it's own first. When you are happy with it's position, take it off, seal all mating surfaces and re-fit it properly.
take off the interior trim panel
hold or tape the pillar support brackets in place while checking that their are no obstructions in the way on the interior. Mark the holes and drill them.
Fit the support brackets to the pillar.
Next fit the mushroom to the top of the snorkel.
Then loosely attatch the round mounting clamps to the upper pipe and bolt em to the mounting brackets. There are small rubber strips that sit between the round clamps and the upper pipe that are MEANT to stop it slipping.
join the 2 rigid pipes with the flexi-pipe without the jubilee clips.
Now is the time to adjust the height of the the top pipe so as to make sure that it isn't so low that the flexi-pipe is creased and it isn't too high that you will take the top off on the first low obstacle you come to.
When you are happy that it's right. Bolt it all down tight.
The rubber grips that sit under the upper retaining rings slip out when you are moving. Either hold em in place with small cable ties or silicone them to the rings to stop em vibrating out.
Finally, remove the flexi pipe and re-fit it WITH the jubilee clips, applying sealer to the joints as you do so.