Thanks for the post.
The stanchions on Minna (B32 2002) are different from how you describe.
They are secured using two screws which can be seen on the deck. I also found rummaging around in lockers fiddly but I found no nuts. I need to do a more careful check when I have some more time to do it properly with a torch and a small mirror.
I agree with the thought on geometry, a 2ft stanchion on such a small base is bound to work loose over time.