[32phil]

I would be very careful in removing the shaft with the lock cylinder in place. The cylinder protrudes into the relief cut into the shaft and moves it up and down.
I have several shafts that have been damaged beyond repair from driving it out with the cylinder still in place.
I always remove the cylinder first.
As 34fordy described by soaking it and then tapping hopefully it will begin to move. I use piece of oak cut to the profile of the face on the cylinder. Working it back and forth over time usually works. Try turning the cylinder with a key may help turn it in place.
All these parts are almost 80 years old and very delicate. I never use a metal drift as they will usually damage or leave a mark on anything they are placed against. Over the years I have received quite a few damaged column drops and cylinders that are unrepairable usually because of improper over zealous removal methods.