Have not read the whole thread, but normally a fishy smell is a loose connection in one of the sockets or plugs arcing and burning the plastic of the socket or plug, switch off your power and take each socket off the wall, give the cables inside a bit of a tug to see if they are loose, when you find the loose one tighten the terminal, it can sometimes be the terminal has been screwed onto the insulation and not making proper contact with the copper, but please only carry out this if you are competent to do so, and DO remember switch off the power first.