Caravan lights misbehaving

Hello. We have a 2005 Concept caravan, and are currently half-way around a Perth to Perth lap of Australia.

Our lights have started misbehaving (it seems after a fairly lengthy lay-up near Sydney) and we are struggling to get the problem resolved. The symptoms are:

- All inside lights are working, except for the LED lights above the kids' beds. These faded over time and then stopped working.
- The inside lights do appear to be dimmer than they were, whether on 240v or 12v, as do the two outside lights.

- The parking lights at the back of the van do not work.
- Nor does the back light above the licence plate
- The brake lights and indicators work perfectly
- Five of the six side lights, and those at the front of the caravan, also work.

- Our fridge does not work on 240v, although the element and thermostat have been tested and work fine. Could this be related?

My knowledge of auto-electrics is limited - but could it be that the power is leaking away somehow?

Any ideas on what I could check for would be much appreciated!

Regards
Paul