Thanks for all of your advice. Time to start looking at maps.
It's all walking distance to me! I've done Waterloo to Camden and back before and I have all day to spare this time. My friends who live in London are always surprised at the distances I walk which don't really seem that great to me. If it was out in the countryside instead of a city, it would be considered a short leisurely hike!
Definitely going to go to Aperture for lunch again. What a great combination. Camera store and Café in the same building!