When I got home I plugged the fridge and things back in to check everything was ok, still no power

I have checked the connections and even plugged something else into the socket to check. I have also had a look at the battery. The only slight thing is the green glow on the leasure battery isn't very bright at all compared to the engine battery.
I'm really not sure where to start looking for what the problem is. Whether the leasure battery isn't holding a charge or if fuse is gone or the back socket has broken.
We have had the wiring up-graded between the leisure battery and the back socket.
I'm not sure were to start looking for were the problem is, can anyone help?
Jon