Re: brake disc uneven wear
Possibly the disk became warped at some point, and thus the uneven wear?
If you drive the car hard maybe consider better brake pads like DS2500's.
The GTV has a similar brake system to the original 156 GTAs equipped with the 305mm discs before they were upgraded to 330mm.
These warped frequently for lots of people.
The standard oem pads can get so hot that they appear to cause warping of the discs.
Of course proper cooling down of the discs by a "cooling drive" helps a lot.
Also especially important is not resting with your foot on the brake pedal when stopped after the brakes are hot, It heat soaks the part of the disc that is covered (and also helps boil you brake fluid). It also transfers pad material to the disc surface.
You could also get uprated discs as well as pads while you are at it.
I'm not a doctor - but I really do recommend braking later