What kind of LEDs to give if you ask? I found in the diagram for closing the windows 1N4004. Suitable? Maximum voltage: 400V Maximum current: 1 A. Housing: DO-41 (through hole)
Connect the two blue wires together and attach them to the brown wire of the new switchboard. The old switchboard already has diodes and fuses - at least in the diagram. How the installer made the connection - nobody knows.