Apologies if someone has already mentioned this before. I'm on my phone and can't check or post a screenshot but I'm sure someone else will do that later! I'm currently at a Sherlock meet in Birmingham and someone has just pointed out a little detail in ASIP that made me very excited!

During the press conference at the beginning, there is a woman all in pink with brown hair.

This makes so much sense. Sherlock already deduced she worked in the media and that she was in London for one day (ie for the press conference), and that was why she was able to leave clues - because she knew exactly what was going on and what was going to happen to her, because she'd attended the press conference and knew all the details pof the case, perhaps a little more than an ordinary member of the public might.

To me, this is just another example of the pure genius of this show. All these little details. It blows my mind!