How often do you see a Ferrari?

Guess you were unlucky, but the areas behind both places you mentioned are where to spot stuff. For reference, if you come back:

Belgravia, Knightsbridge, Chelsea (King's Road / Sloane Street), Mayfair (Old Bond St), Notting Hill (where I live), Holland Park, and Hampstead are the places to spot exotics. If you're only in Whitechapel, Brixton or Stoke Newington, then you'll be out of luck.

 

I see a Ferrari pretty much weekly. Today I saw three, while driving on the freeway, within about 5 minutes of each other.

 

Here in Ottawa I don't really see much, probably a few times a month during the summer, its mostly Porsches and Bimmers around here.