Know how my my son loves Sherlock Holmes I sprang into action. With my trusty friend Mrs. Suzy at my side the intrepid sleuths deduced a way to secret the map to my son.
It’s bigger and more readable here: Holmes, Sweet Holmes: A Floorplan of 221B Baker Street.
Tally ho and off with you to check it out. The game’s afoot. (Kinda reminds me of the Clue game.)
Update: I recomment The Italian Secretary: A Further Adventure of Sherlock Holmes, a new Sherlock Holmes tale by Calib Carr. Last year I bought it for my son, but read it first.