hi paradox
to remove the damaged nut and bolt I would use a four or five inch angle grinder,
with a thin metal cutting disc, I would cut 3/4 of the nut completely off, then change the thin cutting disc for a grinding wheel and grind the rest of the nut and bolt down to the washer then it will come out , use a steady hand gloves and safety glasses , the washer will act as a backing to protect your machine if you grind a tat to much .
good luck damo
