You're going to learn their accents, what low level behaviour means, how a new teacher struggles to find the "positive" and in the end, you'll see some pretty incredible teaching happen. I even got goosebumps.
Then, go through the website and watch as many videos as you can handle this summer. I'd suggest just one a day, so that you can really let it sink in and take some good reminder notes for when you're in London and forgetting everything you've learned. You can also look just at your subject area and the age group you plan or hope to teach.
Some areas that I suggest any new teacher to London focuses on are: behaviour management, IWBs (Interactive Whiteboards), Assessment for Learning and Lesson Objectives. From a Canadian viewpoint, those are the four areas that will be quite different for you.
Have fun with it! If you watch any that you think we should mention, please comment here and let us know.