After John attacks Sherlock in the morgue, there is a small pool of blood on the floor to Sherlock's left. This disappears in the overhead shot.
Lady Smallwood's first name was shown as Alicia in His Last Vow (2014) when Magnussen's details on her were displayed on screen. In the dialogue, however, her first name is Elizabeth. On the business card she gives Mycroft, however, her name is again Alicia.
When Lady Smallwood gives Mycroft her business card, her name is displayed as Lady Alicia Smallwood. As the wife of the late Lord Smallwood, she would be styled as Alicia, Lady Smallwood. She would only be titled "Lady Alicia Smallwood" if she were the daughter of an earl, marquess or duke and had married a commoner, in which case she would never have been referred to as Lady Smallwood. Even if she were afforded the courtesy title "Lady" by birthright and even if her maiden was also coincidentally Smallwood, the rank of her husband would take precedence, and she would never be styled as Lady Alicia Smallwood.
When Sherlock examines the mysterious note, he notes that it is creased from being folded tightly and faded from being pinned to the wall, but the spot of dried blood is still red. Blood is only red when oxygenated, and a spot on a piece of paper would not stay red for very long. When blood is completely dry, it appears brown like rust.