The inside of the left door has been intensively repaired - the filler you can see is over the panel beaten and welded areas - its actually not really filler- its a finishing product called Dolphin Glaze. The nature of this product means its only intended as a thin skim - note it is applied directly over the epoxy primer which is acting not only as a sealer - but a bonding agent. These repairs will last for many years if the vehicle is looked after.