Hi @jmbkiwi ,
Thank you for doing what I suggested.
One other thing that I forgot to ask. Did you change the setting for the type of battery that you installed? If so please ignore this question. Go to Settings > Battery Type (Click on image to enlarge it for better viewing)
I personally think that 12 hours is far too short a time to hold the settings with the battery removed. I may be wrong about this of course.
Most other cameras which employ the same method of retaining the settings with the battery removed all seem to be able to hold them for a least 24 hours if not longer.
Unfortunately as I cannot find a service manual, (or even a video online) on how to dis-assemble your camera so as to gain access to the relevant section in the camera to see if it is actually the problem, I'm afraid that I cannot suggest any other course of action except to take it to an authorized Sanyo camera repair service to see if the problem can be resolved by them.