Kia Sorento XM Platinum MY2011 roof rail corrosion / removal / install

Corrosion has occurred in my 2011 Kia Sorento cast alloy roof rail mounts. As the vehicle is out of warranty Kia Australia do not consider it their problem. From online investigations, it appears Kia UK recognised the issue some time back. Electrolytic or galvanic corrosion in this case is caused by dissimilar metals in contact and is the result of poor design and assembly techniques. When i removed the brackets, the steel mounting nuts had clearly removed the layer of paint on the aluminium alloy brackets during assembly. The reason I show removal of the plastic bracket cover after I had sand blasted and re-coated and re- installed the brackets, was because the original video footage was faulty. The powder coating has provided a hard thick protective coating but struggled to cover the deep pitting from the corrosion. I will be interested to see if I have a repeat of the issue. I was quoted approx A$900 for supply of 2 new rail assemblies (separate parts not available)