thanks will check for movement on the meter I think it is just Red yellow green segments on meter but I would still expect to see needle flicker slightlyI agree, normal to stay on, even if it is not in charging mode, it is supplying power for the lights and sockets. If a voltmeter is fitted, watch its reaction as the power is turned on. It would normally jump up a little, particularly if the battery was run down a bit in advance. eg. battery showing 12volt. Turn the power on, expect around 14.
It looks like it is similar to a old fashion car dash switch that if you put a small flat screwdriver under the edge it should pop out??The switch is a standard unit available from any electronics component supplier. However it will mean disassembly of the entire unit to gain access to it, and unless you are competent and really know what you are doing best leave it to someone who does - and it doesn't need to be a caravan electrician, anyone electrically competent in this area will do.