Took arm to a Motorcycle workshop today, discovered arm is very awkward to use in a press.
Eventually found a way to use a heavy duty socket sitting on the swing arm lugs surrounding the bolt head.
Used a couple large nuts on the exposed threads to give more to push and control how far the press could push the seized bolt.
5 tons had no effect and proprieter was starting to panic, concerned it could slip or damage the alloy mounts on the swing arm.
As it was left a curved mark as can be seen on the nasty last pic, which shows all the abuse I exerted whilst arm was still on the bike.
Namely wrenching the head till it failed, then attempting to tap the head around but only achieving slicing off bolt head material and slightly damaging the arm.
Tried heat but was concerned might melt any seals or damage the base the needle rollers sit on. They look like nylon but coudnt swear to it.
Attempt number 2 my original bodger bastardise the f*cker
Used a regular hacksaw on the bolt head side as was enough play between bearing bush and casting.
On the other side used a junior hacksaw between bearing bush and the end of the T-Bush.
Off came the Pinion block
the bearing bush had the threaded part of the bolt seized inside.
Removed greased and checked bearing using the longest of the 3 bushes, its fine.
Ordered new bolt, new bush and new T-Bush as hacksaw damaged it some.
Started drilling the bolt head left stuck in the swing arm.
Eventually will take the bolt head down to not a lot, wot comes next is for my eyes only [You must be registered and logged in to see this image.]