Wishing the cyclist the best recovery.
There was a cyclist fatality on Catford Bridge, only a couple of hundred metres away from there not long ago. And a pedestrin hit & run not long before that. Those two railway bridges (the bridge over at Catford Bridge Station and the bridge under at Catford Station cause all kinds of road narrowing, humps, bends and so on requiring drivers to concentrate on what they are doing. Not to mention hazards from the bus stops with people crossing and buses pulling out. And nutters turning right out of side roads despite the no right turn signs.
I too generally avoid the S Circular. In fact I often push my bike over Catford Bridge and take the stairs down to the pedestrian tunnel that goes under it.