London - A Day of TopShop

Here is the thing, guys...I'm headed to London this weekend to wear a gorilla suit and run a 7K with my bff, Jen, for that crazy gorilla run thing.  (And hopefully meet IRL her and her!) Honestly, I kind of have Tunnel Vision for TopShop though - You guys are always showing these amazing things from there...and...and so I'm really excited to go - but also a little nervous - I mean, it's our first date and everything.
So I've done some reconnaissance on the website so that I'm kind of prepared for what I'm in for so when I walk in and the fuzzy noise starts in my head and I pull out my money that I can hopefully latch on to a voice of reason (who am I kidding, it will be Marks)..

So...first off - do you have any amazing recommendations for things to eat/see in London?
Second off, and more importantly...which sweater should I get???