steering lock cylinder change
 

I am trying to take out the ignition lock barrel on my 1995 merc 180c class esprit, I have a haynes manual but the details don't seem relavent to my model.
the problem is there is a metal sleeve around the lock and I cannot get this sleeve off.
I have taken off the bottom plastic panel to acces the lock and even tried to take out the steering lock to try and take out the barrel but can't get that off either. any ideas please.