The door latch should not have any adjustment in it, the B post striker is where the adjustment should be made.
With the door latch screws tight, loosen the striker cover plate screws just enough that you can move the striker. Then shut the door firmly but carefully, maybe give it gentle pressure to hold it in the shut position while you then release the door catch before opening the door without moving the striker.
Carefully tighten the striker plate screws & try the door closing action. Maybe need to repeat the process for best results.
Poor alignment of the rear edge of the door so that it does not sit flush with the bodywork is very common - both my cars have it! I have improved it by setting the closing action as best I can, but I think complete perfect alignment might involve adjustment of the hinges at the front, which is a whole lot more difficult!
Tony
<font size="1">1981 2L FHC Cavalry Blue
1980 3.5L V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">