Yup - I went over some nasty bumps as I walked the bike along by the house-boats in Little Venice - and when I got back on my trusty steed, there were the tell-tale signs. My chain was "whirring" whenever I pedalled. I couldn't get into my third set of gears. And the clearest sign of all? I was rapidly losing my temper and therefore my karma. To cap it all, when I stopped and then re-started, sometimes my pedal would be "loose" and I'll whack my nether regions into the saddle. Pain.
Anyway - I've tried shoving the wretched thing across, but to no avail. I now need some advice on how to bring it back to a more workable state. Anyone an expert on derailleurs? Otherwise I'd better do some investigations.
Karma rating: poor.