Thanks Bill, Alan and Tom Fisher (offline) for your help,
I was able to remove the inner sleeve (my terminology might be not accurate) by soaking the unit in kerosene over-night and using a vise to push it out the 'top' of the outer shell. 'Top' meaning its orientation as it would be if the mast were up. See pic of swivel in vise and of the separated pieces after the fact (the inner sleeve is top end down in the pic, sorry).
Now, I'm looking at using a 'blind hole bearing puller' to extract the topmost bearing. I'm not sure how I'll get the bottom bearing out - maybe with a dowel as suggested by Tom F or figure out how to extend the length of the puller.
I've measured the diameters of the bearings so I can get the correct sized bearing puller.
Inner diameter = 1.75 inches = 44.45 millis
Outer = ~2.25 inches ~= 57.15 millis