Just say yes, just say there's nothing holding you back

As I mentioned before I'm going to visit London in one week and I'm so exited.
It's not my first visit and I love to come back in my favourite city in the world.
Well, it's a class trip and we stay there one week. And one thing I'll do besides sightseeing is shopping. Of course! You wouldn’t? The first thing I'll buy is the obligatory "I love London"-T-Shirt because mine - which I bought back in 2008 - shrank while washing.

I wanted to take the chance to ask:
Does anyone of you have some shopping tips for me?
Where are your favourite stores? Markets? Thrift Stores? Must-sees?
Go ahead!

I will post reviews to the stores and markets I’ll visit after I’m back home.

Snow Patrol - Just say yes: