Now in use and confident that it would be very difficult if not impossible to remove any deliveries. 2 extra holes in the middle of the back plate would be good additional security for fixing. I used a piece of card to make a template of the holes so if this was included it would be a bonus. If you are securing this at height make sure you have someone to help or something of a slightly less height to rest the product on as it is awkward to hold solo with the door open. I had to lubricate the lock whilst locked to get the door open as it was quite stiff. All in all, very happy with the product. Good luck.