That you to have been able to remove the lock retaining screw, the door must have been unlocked & open. Simply put a screwdriver into the keyhole & twist to 1 oclock or 11 oclock depending on side & push. This lines up an offset lug & will not need any force.
martin
May 2011
i normally hit the top oh a of the barrel hard and it will just snap in 2 after doin this u will c a little black ring inside remove that carefully ideally with a screwdriver and then fit new cylinder 7 seconds my record doing this 18 years in the business
chris
May 2011
You need key to remove or drill it out. Drill just above the part that turns, that should cut barrel pins. Turn to 1 o'clock & slide out.