Some things I might check before adjusting the hood are whether or not the spare tire and battery are both secured properly. If not, tighten them down and see if it cures the problem.
If not, yes, the hood closing height is adjustable - but if you're not getting a whistle noise above 40-50mph, then your hood's alignment is correct, just the buffer zone is not. Therefore, I recommend you only loosen (counterclockwise 1/2 to 1 full turn) the black rubber stops (2 - one each side) in the forward most corner of the hood. Maybe a little more if necessary, but shouldn't be too much. Close hood gently to make sure they clear and tweak as needed.
So, if you still want to adjust the hood's height, there are two nuts for the latch in the trunk. First, you need to remove the black plastic cover near the hood latch (see front bumper removal in the Bentley). It requires turning two (maybe four - I can't recall) black plastic heads 90 degrees and then lifting it out around the red latch for hood release. Then, pull back the carpet lining in the trunk and on the front side, you'll see two 10mm nuts. Just loosen both and slide the latch down a hair and retighten. Before you close your hood to test, make sure you adjust (screw in clockwise) the rubber stops on the hood's corner
