Picture of the rear..
the comm diameter has shrunk quite alot due to the lathe work whilst it was getting hot and trying to find the problem which is when i gave up!
the rust? your guess is as good as mine - i look after all of my motors and skim/clean often just to keep them in good condition so i really do have no idea.
i will try the arm.. but i am still warey about if it is an orion arm. as they ussually come stamped? this however dosent.