I was washing the car today, should have done it 2 months ago.The paint seems stained yellow, you can see were something has run down both sides of the car. I think it is from the grit and slat or I am running DF 3000 pads which are heavy on dust prehaps it is them.
Has any body else had this???

Most likely from the pads.

I had the same problem with the 3000's, they have a large metalic content, if you stamp on the brakes in the dark you can sometimes see sparks flying past the windows. This hot metallic substance sticks to the wheels and paint.

You are going to need a good polish and lots of elbow grease to get the paint back to normal. I ended up washing the wheels daily and the car every few days with a polish every couple of weeks to keep on top of things with 3000's fitted.

Lots of people on here swear by Wax Wizard products but not heard from him for a while.

Lee