I guess that's why they are so costly, but I wonder if a plate with 3m VHB would be quite a deterrent as it would be very difficult to remove and would help with the "move along to one that looks easier to have a go at" mentality?They come with 4x studded rods welded to the back which drill through the outer door skin.
These have rectangular load spreading back plates. ( Fancy washers) and nyloc nuts which bolt on from the inside. They are measured so they don't interfere with the internal lock mechanism.
The back of the front plate has 3mm neoprene foam... This is to take the play in the curved van panel as the plate is dead straight..... Instructions stay don't over tight en.