Yep, like Tombeau, I used the Dremel to get the washer off and then replaced it with a tight fitting rubber washer to hold it in place. It works fine. Actually I also fitted a nylon washer on the outside under the dzus fastener head to avoid scratching the new paint as time goes by. I recommend that mod.
Alan.
PS just remembered, I also have a wire from the inner tool box casing to the dzus fastener to restrict the lid from opening too far and damaging the hinge etc.