For those of you that want a simpler solution to the issue of brake dust, I have the MSport brakes and was getting my 21's covered after only 3 days of driving.
I did a bit of research and found this stuff;
Armor All Shield Brake Dust Repellent*(
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1)
Since using it my wheels now stay brake dust free for the entire 2 weeks between washing, it might be an option to those wishing to stay OEM.
*FYI- not affiliated in any way, just a good product....