In the main switch panel, just pick one spare MCB and then connect it to a SEPARATE switch panel with a main switch, a RCCD and also N number of MCBs connecting to N number of wall socket via Prysmian or Pirelli 4 sqmm cables . Very simple! You will get much more quiet sonic background.
Ir should be better to use copper pipes to house the Prysmian/Pirelli 4 sqmm cables but PVC conduits should also be good enough!