head to your most OG boardshop around and ask if they have a box of ancient burton bindings laying around or a bunch of spare parts. i know my boardshop does. the boardshop has been around scince '88 the bindings weren't that old but they were like early 2000's to 2005ish probably. but if you got a dealer they probably have a bunch of spare parts laying around in drawers and stuff where they keep parts. Dont say a burton P1HD binding from 2004, cuz they'll prob just say no but say you need an old toe ladder and explain it to them, that should help
edit: make sure its a burton dealer that has been dealing burton for many years.