Londondrz - I don't live there, as I've already mentioned. However one of my children attends one of the nurseries on those roads so my family visits daily. I've never actually seen someone go the wrong way down Manor Mount but I've seen plenty of (and had near misses in relation to) speeding traffic along Waldenshaw Road/MM/David's Road to avoid the lights on the South Circular.
I mentioned restricting access mainly as a suggestion that no one else had brought up. Default thinking in this sort of situation thinking tends to be car oriented and I wanted to give some air time to an alternative point of view. At a time when over a third of car journeys in London are less than 2km and we have epidemics of obesity, inactivity and air pollution, I think options that reduce car use are good.
I also think that the area where I do live would benefit significantly from a few strategically placed rows of bollards to cut out through traffic. Roads where people live should be just that - for living, not for through traffic. A single access and egress for motor vehicles would suit me just fine. The extra time required for some journeys would be a small price to pay for a safer street for my children outside their front door.