The solution is quiet resignation. I need a new swing arm. I did try heating with a MAPP gas torch and putting a slot in the end of the bolt. It would not move at all. It was moving last week. When I took the tire off and loosened the slack screw half the bolt just fell on the ground.
What I am going to suggest to be successful will largely depend on your skill level. I have looked in the manual and can't find what size of bolt, it looks like a M8 bolt, assuming that is the correct size ( you will need to verify it is), you would need to buy a long 8/32 and long 17/64 drill bit, you would also need a M8X1.25 tap (I called the dealer so know it is a M8X40, don't know thread pitch but looks like 1.25).
The reason for the long drill bit is you can't drill in straight without the drill chuck hitting the swing arm. Next is a trick I have used for years on taps from 1/4" to 3/4" , you are going to need to buy some replacement bolts and nuts, get a couple extra nuts.
You will need to find someone with a large shop vise ( 4 inch opening) or a arbour press, take a M8 nut and your tap, place across the 4 inch opening with the nut on top of the tap, tighten the vise and once it becomes more difficult to tighten you have succeeded in pressing the nut onto the tap.
The reason for this is the same as for the long drill bit, a regular tap handle won't clear the swing arm on a straight angle. With the nut pressed onto the tap, you can now use a socket wrench with extension .Take your time and I would suggest using WD40 or a tapping oil.
As a last resort, if the above doesn't work, you could go with a longer M8 bolt with full thread , same as OEM full thread bolt but longer( assuming you now have a clearance hole with no thread), you would then need to use two wrenches for adjustment and also loctite after so the bolt can't loosen and fall out.