Oh, thanks Davina I hadn't seen this thread.
On reflection, I agree with ukaunz in not thinking that Sherlock had registered to take up The Knowledge. I've tried imagining cruising the streets of London on a moped with a map and...no. I do stand by the idea Sherlock would have thought it interesting enough to chase off boredom (and useful, if considering his past), though.
On a side note, that's something I feel I'd be useless about, considering I can't read a map without losing myself -little to no sense of direction...*buried under the weight of my shame*