Hi Paddy
Welcome to the forum.
For a definite answer, can you let us know which panel you have fitted? It should be written somewhere near the top edge. My guess is that when she is plugged into a shore supply, the green light will either tell you that there is mains power coming in or, more likely, it will indicate that the domestic batteries are being charged (perhaps when the breaker is switched on). The charger is possibly on a shelf under the chart table.