How about this? Clearly NO LENS CAP!
Yes, thank you very much. That is the sort of thing I had unsuccessfully looked for.
If that is the extent of the problem then I can easily live with this. When taking long exposures like that I would generally use a 2 second delay to make sure that I am not shaking the camera. There would be no need to leave the back light on during the exposure.
Actually, I would probably be shooting manually, so changes to the auto exposure wouldn't matter anyway, but it is good to know the limitations and bugs of the camera.