How depressing that today's graduates think like this. Whatever happened to rock n roll?
OP you are looking at this all wrong.
Go to London. If I have to spell it out, you'll get much better networking opportunities, you'll experience this great city and all it has to offer (culture, diversity, opportunity and all that) and - most importantly of all - you wont spend the next 10 years of your life looking across the table at managers or interviewers who secretly find you suspicious because you never spent time in a London team.
Give it a few years in London then go to the regions if you want to. You'll be more polished, better networks, and really know the value of green spaces and no tube commute to work.