Srobarts
It sounds to me like whoever designed your installation got the wrong configuration of board. The main breaker should be just, not an RCD and all final power circuits should be protected by their own individual RCDs, lighting circuits should be protected by MCBs, usually 6A. This is to prevent the house being plunged into darkness due to power fault and allows you to identify individual faulty circuits while maintaining supply to the rest of the installation. Discuss with spark who comes to (unnecessaryily) renew socket.