You'll find that the other one might just come off without a problem... It was like that on mine, but you could be unlucky and run into the same headache. At least you got warned before hand about the arms balljoints stripping the bolt and the gap causing problems. At least you didn't mess up more than a boltDONE. Thanks again for the advice @northpole as I used a blowtorch to heat up the area and a clamp to squeeze it just enough to close the gap slightly. This worked and along with a new M10 bolt grade 8.8 and using the same clamp to ensure the arms were seated properly all good. I thought I took some more pics but must have forgotten as it had just started to rain and I was keen on putting everything away. And yes, it feels firmer and so much better, can't wait to tackle the other side... NOT.

