Running up to policemen in Trafalgar Square to ask them exactly where the Canadian Consulate is may well be a good idea. However, spotting the large Canadian flag outside before you ask them is even better.
Mainly though, that there is a strange cycle in these things. Stuck at Paddington for a while allowed me to loiter by the spot where
But Oooooo! Nice Serenity posters all over the Tube walls though.
And I did get to read Terry Pratchett's new book : Thud. Excellent as ever.