This is the panel I mean. I removed the rubber bump stop above the fog light because its base was rusty. Therefore the aluminium skin is now corroded where it was located. I nw think I will sand it and fill it with a P38 skim, Upol Dolphin Glaze to finish and a coat if marine blue. I thought the corrosion was coming from steel behind the panel but I think it’s from the bumpstop. Replacing the panel is beyond me.