I needed to replace a nine year old mortice lock. This lock exactly met my required dimensions so I was so pleased to be able to buy a suitable replacement without further woodworking. Once in place I realised the catch was facing the wrong way round for the door closing requirement and I could not see how to correct this. A professional locksmith would have known immediately. I did not see reference to this problem in any instructions but eventually realised all you had to do was grip the catch with pliers, turn the catch 90 degrees, and snap it back in place . Sorted. Very pleased with this purchase.