Do you know when you use the most electricity each day? If you’re out at work during the week you’ll hardly save anything during the day and get penalised when cooking your dinner
My late FIL had a serious damp problem in their lounge. To see the other side of the wall he went on the roof and could see that the adjacent neighbour had piled up garden waste against his wall.
One polite conversation later the neighbour removed the garden waste and a couple of hot summers...
Cumulative leakage across all those circuits wouldn’t surprise me in the least if the old board had a single up front RCD.
At least now if something trips you’ll know which circuit and all the others will still work
Thanks for the update - it’s good that you’ve done this
You might find the switch drops are in metal conduit so pulling new cables would be much easier.
You need to “brief” the spark doing the EICR on what you want to know, then allow them the time to investigate properly