I have never thought about using 100lb test fishing line before. That’s an awesome idea! Thanks!Trailer hitch pins for want of a better description is what I started typing earlier and it all became quite confusing due to the terminology from across "The pond".
The pins we use to secure our trailer number plate boards with some heavy 100LB breaking strain fishing line (doesn't rot) attached would suffice.
Securing the screwed rod will only need a vice and perhaps a small 2mm hole 3mm at tops for using the pins. The secret is to very lightly grind off the threads on opposite sides of the rod ever so little. Hit the flat part with a small centre punch, just enough that your drill bit will get a grip and apply light pressure. The hole will be drilled in no time at all and fitted the rod reinstalled.
Fit the boards and fit the pin