They are not getting approval from the JLR factory. They would be getting approval from your regional/market office... where ever that is. For instance here in the US our regional/market office is LRNA in New Jersey. It's no different than second gen L322s that had issues with condensation buildup in extreme temp swings. Most of the time condensation is simply burned off or vented. If this did not happen, some were changed out as a courtesy. However they certainly did not change them out in pairs.
If this were a design flaw we would see many more posts on these assemblies clouding or discolouring.