If you haven't read the scamp
website, it is pretty informative if you dig into it a little bit about the various systems in a scamp.
I'll second that the top picture is a 12V outlet similar to what is in most cars. The bottom picture I only have guesses and would need more pictures and information to determine what it is. However, someone else on the forum may recognize it.
The water holding tank usually gets water out one of two ways. First, there can be a hand pump usually near the sink. Second there is a pump that pushes the water and typically there is a switch to turn the pump on/off. You can follow the water lines and usually find the pump.
I'm generally decent with amateur electrical
stuff and willing to answer questions if you have the time.