Good idea but remember that most of the halloween celebrations in london will be on the sunday so we may be the only ones dressed up also we might not get the sort of crowds that we got last year if we turn up a day early
From my experience of london on a saturday night it is the lads lets get drunk night and you get a lot of rowdys
One other thing to concider is you will have to pay for parking on a saturday (if your bringing a car to transport costumes etc) but on sunday it is free
I don't mind doing it on saurday but will be going by train if we do as driving up there on saturday is a nightmare and I won't pay £30+ to park for a couple of hours and I have the option of leaving my gear at work a few days before
Jason