ive just used fat mat(like dynamat) sound proofing in the doors, not insulation
the whole van has taken 200 sq ft of sound proofing
the bubblewrap just gaffer taped to the sound proofing, its roof insulation silver bubblewrap, apparently 1 layer is equivelent to 120mm of polystyrene (which is what ive used in the back door panels and sliding door