They could be the wrong pads ? If it has the same effect on both sides, if on one side only, if they are a two piston type caliper, maybe only one piston is working and the other is seized, Is it the same on both front discs?
2011 Kia Sorento KX3 2.2D 60 Plate Auto in black ( mine )
BMW E83 X3. 3.0d M Sport, 2008 in black ( now gone )
BMW E93 330i Convertible Msport 2007. ( Now sold )
VW Golf 2.0 TDI 140 GT 2010 ( now sold )
Now Sold 55 plate, X5, 3.0 D Sport. Silv
Looks a bit weather beaten
Does the wind driven rain hit that side of the car , I have the same issues with a couple of cars if not used every day .
The pads will still grip on that surface as you can see in the pic but they will wear faster .
There trims available which fit on the inner rim . These will keep the weather out .
There is a UK supplier if you search
From the picture and the reflection across the whole usable diameter of the disc your pads ARE biting on the whole disc- now!
My guess is that the previous set of pads were jammed in the caliper- thus not fully making contact with the disc. New pads installed but disc not skimmed/ replaced. The pitting in the photo is below the level of the top surface of the disc.
It will eventually (after many thousands of miles) wear the disc down to an even level. Of course braking force on this side will not be as high as the opposite side- but barely noticeable.
I would measure the thickness of the disc and if within the limits have it skimmed.
Let us know how you get along.
HTH
E70 3.0D SE, Black with Black - Gone but not forgotten! >:D