M: (to Holmes while being interrogated) He sends me coded messages on me cell phone.
If M had only just come from England and is talking to another Englishman (Holmes) then he mostly likely would have used the term "mobile" as it is called in the United Kingdom and not "cell phone".
Sherlock makes a reference to M's vintage driving gloves not being as expensive as his John Varvatos shoes. John Varvatos is an American contemporary high fashion menswear designer.
Watson's e-mail from Sherlock's father in Britain states "... you may expect your final check presently". Since the 19th century, the spelling "cheque" has been standard for the financial instrument in the Commonwealth of Nations while "check" is used for its other meanings (test, make sure, safeguard, inspection, curb, bill, etc.). In America, the spelling for all meanings is "check". Sherlock's father would most likely have used the spelling "cheque".
M: You're a rare thing in this world Holmes. You're an honorable man.
Holmes: A famous statistician once stated that while the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty. You can, for example, never foretell what any one man will do. But you can, with precision, say what an average man will do. Individuals vary, percentages remain constant. So says the statistician. I am not an average man.
Watson: What are bees doing in here?
Watson: No. I mean, why aren't they on the roof with the others?
Holmes: I'm seeing how the indoor temperature suits them. Our six weeks together are very nearly up, Watson. In a matter of days, your room will be vacant. I'm very seriously considering turning it into one large apiary. Finally the space will serve a purpose.
Watson: Oh, you say the nicest things.
"Me And The Devil" by Gil Scott-Heron (final scenes)
Original International Air Dates:
Canada: January 10, 2013 on Global
The Netherlands: March 5, 2013 on SBS6
Czech Republic: March 26, 2013 on AXN
Germany: March 28, 2013 on SAT 1
Sweden: September 2, 2013 on TV4