Thanks but that will have to be my plan B as I am in the UK and the boat is in Greece at the moment. I was hoping to buy a switch and take it out with me next year. I did have a peep behind the panel when I was out there but couldn't see anything obvious.
Ok, it’s a 2 pole version, made by Carling Trchnologies. Go to mouser website and key in part number, they may have it. If you go to carling website you can download a spec sheet which explains the numbering system. I could not get the exact same part, but one which was the same in all respects other than the thread type for the fixing screws ( USA thread, rather than metric m3)