How can I get my Neff built-in oven door to shut properly?

My Neff oven B-AP22-7, E-nr B1421NGB/01 has a drop down door which has always been sloppy and does not close tightly. Removing and replacing the door (as per the manual) has not improved the closing. The hinges do not appear to lock in position and the door is now too low to shut effectively. Any ideas?