For working on the electrics I have to take that board with all the switches and cables out of the car. It has been easy to remove - just one screw at the top, and I could take the board out and work on improving the electrics. But everytime I took the board out, I also had to unscrew several electric connections: vehicle ground, vehicle battery, leisure +/-, solar panel +/-, lamps. The cables are not getting better from often removing them form the screw-terminals, so I was considering to use plugs instead. I found several connectors at Maplin which were suitable for the lighting connections (ok for 6A) and the solar panel connection (20A is sufficient, as I have seen never more than 6A coming from the solar panel). But I was not able to find a suitable socket and plug for the battery: I have designed everything to be able to support at least 30A (solar controller, thick cables, circuit breakers). Therefore I was looking on ebay, and I found one, shipped directly from China: a heavy duty connector with four pins, used foe 380V and permitting 30A.
This connector is also waterproof. So I connected the leads from the two batteries into the socket, and connected the plug to the board.
Now it takes much shorter to get the board out: simply unplug all the connectors, remove the one tightening screw, and the board can be removed.
And while at it, I also added a cover board to hide the cabling out of the view. And improved the attachment of the board: now with two screws (one at the bottom onto the work surface, the other on the top onto the shelf.