This was one of the flash failures on 26th Aug. The on-camera flash is supposed to be the master and there was a slave on a tripod to the left. This one had the on-camera flash bounced off a built-in reflector. The slave didn't go off though and the ratio was set something like 2:1 to the slave, so this ended up underexposed. Still, it's rescued quite well - and now I've got it, I think it's better than the one I chose for the PaD. D'oh.