The factory installation method was to run down the nut tight and then hammer on the threaded end of the screw to mash it out a bit. Which makes them really hard to remove without wrecking or breaking them.
Agreed. Now I’ve had a longer look at it, should be easy. I’ve managed to drill out the peened leftovers and threads are fine. I’ve even got a long 1/4 unf bolt I can machine to fit