I guess film rights are not negotiated like that, BUT artistic freedom. (In fact, I don't have a clue how that really works).
"Sherlock Bits" blog: [link]
"Sherlock Bits" on Tumblr: [link]
DISCLAIMER: Characters (c) BBC / Arthur Conan Doyle // Character design made after actors // Art and idea (c) Panagiota Giannakidou. I don't earn any money with this.