Unfortunately Alex is spot on with this.
I have a big brake kit which only amplifiers this problem.
After changing discs/Pads twice and trying my best to clean the hub faces the problem still came back after a few hundred miles.
I ended up having the discs skimmed in situ on the car and have had no problems since.
The guy in Winchester who runs the company said he is very busy most weeks sorting out fairly new and very expensive sports cars with the same issue.