Internal blog post
Further information on the the keypad lock – from Phil Richards

The locksmith has serviced the keypad lock and it's OK for the moment. If the keypad numbers stick, you can bang the door with your hand if you are happy to do so that should normally release the keys and input the numbers again having pressed 'c' to clear it. It is good practice to always press'c' before entering the number to help the lifespan of the lock.