Eolia centre plate removal

[michaelw]

How is the Eolia's centre plate swivel attached to or removed from the cast iron keel?  I can see a square plate either side of the keel.  One is fixed with a stainless steel bolt, the other appears to be welded to something.  Once the bolt has been removed, should the swivel push out towards the welded plate or is there more to it than that?