Same problem for me. However my second file I had to create got past it. In my original game when I approached the door I had knocked twice. I got the first speech then pretty much the same speech once I hit x again. The guy walks to the back and talks with Dorothy, who was invisible, and then no prompt came up after wards. I went to the safe house and when you walk out and it loaded back into white chapel I got the prompt to investigate Darius. He just stood around his house doing nothing.
Second time around I just knocked once and then used the vampire sense. Got the scene with Dorothy where she was visible and now I’m able to continue.
I don’t know if that really helps anyone... but there you have it