I disagree with the criticisms of LRK here, in re a lack of research about skin dye. This seems to me to be like Hamlet dispensing with his opposition off-stage so he can head back to Denmark. (R&G, they're dead, you know?) It's not important to the story, so nod to it and move on. Okay, avoid blatant impossibilities, but I'm okay with the suggestion that "yucky skin dye exists; they use it; it works". An SF writer might have pickier reader standards to live up to, but not a mystery writer who's repurposing Holmes to give him a love interest.
An example of a detail that does not particularly need to be perfect to keep the fictional dream chugging. Though perhaps she's a sloppy writer in other ways.
But in the end I come down on the same side as singer_d: Doyle's Holmes is a very different man from King's Holmes. She's writing fanfic (cough, excuse me, pastiches) so that's fine. We're all okay with it. But I prefer the original.
Probably because I am fond of Watson.