Here's a couple of pics of the "Mould Release Line" - First Pic shows one end of the door, with Two Lines marked with arrows, The other end also has two in the same positions. I have found that the one shown here on the Left is the one that causes most leaks, but its easy to fix all 4 while you have the sand paper out !
Second Pic shows a close-up of the Left Hand "Mould Release Line". When it is sanded this line is no longer visible, and you can't feel it when a toothpick is run along the groove. I have now heard from around 15 people that I did this modification too their housings, and all have done plenty of dives with absolutely NO LEAKS.
P.S. Please don't ask me if I can fix your housing "Mould Release Lines", it is so very easy to do yourself.