Undo the x19 T27 screws to the undertray then remove the undertray.
Facing the front of the car, undo the bottom and top 10mm nuts to the left side of the plastic auxiliary cover.
Now undo the mid 10mm nut on the right side of the cover, about two inches to the left of this you will find the last nut.
loosen off the 7mm nut on the jubilee clip to the turbo intake hose with a flexi driver (the nut may be hard to reach).
Undo the x4 7mm screws to the top of the air filter housing.
Unclip the x2 breather pipes to the turbo intake hose (push release). You can now remove the air intake pipe.
Lift out the undone auxiliary cover.
Place the end of a 3/8″ breaker bar into the square hole of the auxiliary tensioners lower face. Rotate the tensioner clockwise to release the tension on the belt then slip the belt off of the idler. Extract the old belt from the back of the tensioner.
On the new auxiliary belt you will find two places where you can see the stitching….this is normal.
Re fit the belt making sure it’s routed properly and runs OVER the idler, pull back the tensioner again with the breaker bar then slip the belt UNDER the idler.
Using a 22mm socket on the bottom pulley nut, rotate the pulley clockwise a few times checking that the belt runs true on it’s ribs.