Hello Colin. Sounds like the cylinder has failed. Open the door, remove the cylinder by removing the screw in the edge of the door. You will need the key to do so as you will have to turn the key about 10 degrees left or right to pull it out. Replace the cylinder wit a new one but check the cylinder in your hand first. Will it work when not in the door? Dont forget to measure the cylinder and if in doubt take it with you to a local hardware shop or Homebase/ B&Q etc.
Paul, March 2011
Take the barrel out & see if it work ok, if not buy new one, to get it out, open door & you have 1 screw on edge of door holding it take that out put key in & turn to 1 or 11 oclock (depending which side you are) now pull it out.
