Extreme sympathy to h_w for a horrible experience. I think you did exactly the right thing in (a) informing cabbie and his customers of the danger as loudly as possible, (b) avoiding a collision, and (c) stopping to collect yourself before continuing your journey. Shame not to get the plate, but your here and unharmed.
On a more positive note, I fixed someone's snapped chain in true Bicycle Repair Man style, but with the modern twist of latex gloves and compact link removing tool. Bit late for work, but nothing compared to how late he'd have been if he'd have done what he intended: walk to the nearest bike shop (8am, Colliers Wood).
More generally, has anyone else noticed sociability blossoming with the Spring. Through the Winter I've been through weeks at a time without exchanging a word with a soul. In the last week I've been spoken to (they started it) by a lady on a Pederson, man on a 'bent, man with 100" single speed, three people asking about my 'guards (they are very exotic), another lady asking about Carradice, and four or five regulars who I haven't seen for a while. Cool!