how to remove lock barrel from door lock

I am trying to remove the barrel from this door lock - the PO had lost the keys, so i plan to replace this barrel and the one in the tailgate.
Anyway, i can't work out how to remove it.
I read somewhere that i need to push the pin out. Is that the pin in this photo? i
f so, it doesn't seem to want to move. Do i push it out from the other side, or do i push it through?
In either case, it doesn't appear to want to move.
Is there another way?

I think I can see the crosshead screw in the center of the shaft in your pic. Undo screw, put key in lock and wiggle it out, no key jam something in and wiggle.
The pin you mention is a different version [ on barrel itself ] accessed through a small hole in the barrel housing and pressed in.
Videos on youtube. There are different types.

You can see the top of the roll pin on the side of the latch in your photo. It has to be knocked out with a suitably sized pin punch.

The circular slotted nut behind it then has to be unscrewed. A few taps in the right direction with a pin punch in one of the slots will loosen it.

The barrel can then be removed. I had to do exactly the same for the rear door when I first bought my Series.