I wouldn't waste your energy trying to pursue this further; people have been complaining about it for years. There was even a public traffic consultation a couple of years ago on behalf of the local Ward Assembly and the issue was raised then too, but the answer is always the same: the bend isn't suitable for a crossing.

I think you got a decently detailed reply from Lewisham. The fact is that the bend is such that drivers wouldn't be able to see the crossing in time to stop safely - although that begs the question how do drivers see pedestrians crossing there now, without a formal pedestrian crossing? Perhaps the experts think if there were a pelican or zebra crossing pedestrians would take less care judging the speed and distance of oncoming traffic and just step out onto the crossing, presuming that drivers would stop in time.

And another argument against a zebra crossing is that during the evening rush hour when people are coming off the trains via the platform 2 exit, there would be a steady stream of people crossing the road and this would hold up the traffic.

Although we perceive crossing the road there to be potentially dangerous for pedestrians, I haven't heard of anyone actually having an accident. Perhaps that's because we know it's a bad bend and take extra care when crossing!