Carver 2 Water Heater

Making use of the van we had lunch out today. I put the water on to wash the pots and every thing worked as normal, hot water in about 20 mins. After lunch I tried to turn the heater off by pressing the left hand button as normal. It wouldn't turn off.  After a bit of thinking I turned the leisure battery off on the panel. When I turned it back on the heater was off. This will do as a temporary cure but I think I am heading for a new switch. Any one like to add to my thoughts.