Mandie_R: I would enter Manchester now - the odds are you won't get into London, and even if you do, you can defer.
I'm going to give it a miss this year - only because I have a place in Brighton, and already booked a hotel room for me and the family. But I've volunteered to help, and hope it runs again in 2013.
For those who don't know the area, it runs ou through the suburbs, and through the edge of leafy Cheshire.