Whilst I was there I walked through the torque settings for the front and rear suspension - see Torque Settings.
[Postscript - 20th Aug 2012: Guidance from GBS was to remove the powder coat down to bare metal at the ends of each bracket. This done there was still insufficient gap on the off-side so I needed to remove a little more. The disks now spin clear and even within the calliper.]
I spent quite a bit of time scratching my head over this, which has limited my progress this weekend, but I did manage to tap the front upper wishbones. The threads in both were full of powder coating and refused to accept the ball joint. I ordered a M18 1.5 tap from Hong Kong which came on Friday. All is now clean and the ball joints spin down the thread unimpeded. Another oddly satisfying problem resolution.