That is great advice. I think I have brought exactly that repair kit from halls.
My plan C was to carefully cut off both end cups to create a space between the a arm and the upright to allow hacksaw blade width and cut through the shaft. I could likely cut between the heavy end washer and the end cup which would also protect the a arm as there is a small space there where the o ring washer sits.
I am over pumping up the pressure waiting for the casting to burst!
I will get the 321 SS replacements made up as well.
Thanks so much Bosswrench - I will let you know how it goes.