This customer’s lock looks a bit old, but it conforms to BS3621. The people have just bought the property and had been told that a lot of keys were in circulation for this door. The lock is a “Yale” British Standard sash lock, and a we could have supplied a new replacement lock. The lock was in good working order and I saw no reason to replace it, a new lever pack giving 2 new keys and ensuring the old keys don’t work retails at around £30. I stripped the lock, changed the position of the levers and cut 4 new keys, less than a lever pack and the old keys don’t work!