Two weeks later, I was still faffing about with it and not getting anywhere.
An unrelated disaster also occurred on Friday 13th September 2013. My Canon Powershot A650IS, in use since 2009, developed a fault. It still worked, but the screen broke down. I was having to use the A/V output on the camera to show the screen on a television through composite video, which was a bit inconvenient as it isn't normally particularly handy to lug at 14" portable around with your camera. This is the first picture taken after this disaster.