We've got three kids, eldest 8 and youngest 3, and have never had a car. As you say, in London it is mainly fine, it is the trips away that get complicated. We are on on my mum and dad's insurance who are in Cambridge so sometimes will train it there and then borrow the car for a couple nights but wish zip car worked better for these type of weekend trips....looking forward to seeing how others deal with the trips thing....train journeys have definitely improved with the iPod and iPad!!