You are right Roz about there being a lot of work for a few people. A core group of 4 or 5 really got things going but they used an interesting tactic of leafletting every household several times, including just before key meetings and managed to get others on board. I think 15-20 were involved before the day.
Of course if it is repeated it should get easier each time. I went to the Walters Way (self build houses off Honor Oak Park) street party on saturday, which is an event of 12 or 13 years standing, and by now everyone knows their role. It runs very smoothly and planning is probably minimal compared to the first time around. I also think they would challenge Michael and Calvin to the friendliest street award! They have a very strong communal life. Regular events can only help this aspect. Probably not a bad thing to get competitive about.