what will you need for good observational surveys in seemingly concentration reppelent places.

. A note book to jott things down in
. A straight face for looking clever
. A plain black/very navy blue satchel bag(rucksacs suck)

Be prepared for and more suggestions later! Feel free to post your own.
 

It has come to my attention that we need a good theory.
Well here it is.

First, sherlock slowed his heart and pulse to an almost state of death. Next, he waited untill he could feel the rate of his heart fading, his life floating away and pins and needles all over, and then jumped. Snagging his foot on the building, he broke his leg and smashed his head on the truck below, just above ground. Because of the pins and needles, he felt no pain and crashed harmlessly on the ground. Blood seeped from his wounds giving the impression he was dead. Blood everywhere, skin as white as ice. seemingly dead. they assume he is dead because, afterall, no-one likes to see some distant child's role model lying on a surgery table being cut open to be sure they have kicked the bucket(or snuffed it, as he did with Henry Baskerville's ciggarette in the preivious episode)