Posted 18 June 2012 - 12:44 PM
It has been a while since I have done this but from memory, that part you are worried about should be the actual "lock pawl". I believe what you need to do is put the key in the lock and turn the barrel until you find a brass pin that can be tapped out to remove the lock core. If you don't have the key anymore, you may have to pick the lock to get the barrel to turn. The key is also the tool used to pull the lock core out of the housing.
While I have been told there should be lock numbers on the cores, I have never found them on the British cars I have owned. I ended up buying a re-key kit to get my locks set the same. That is a separate story in itself as I was advised to buy the wrong kit... but again, that is another story.