Ok, things I have found affect the bloody awful buffeting.
Stock screen, for me was way too low and put the air into the chinbar of my helmet.

I changed the screen for a Metal Mule tall screen.
It still wasn't great so I used a heat gun and an aerosol can to form a flip to the top, and flare the sides out.
Improved.

I also fitted a Kriega tank harness and US5 bag to the tank to help disrupt the air flow through the post-fork section. Made a tiny bit of difference.

I also found that suspension settings made a difference. If the front was too soft, or the rear too hard then the attitude of the bike was changed. Ideally with them equal in sag then not only do you have a better handling bike, but the buffeting decreases.

The buffeting is probably the very worst par of the bike, and it is a real pain until you get it sorted.