That sounds scary! The RCD should protect ALL the circuits - unless (like me) you have several RCDs on different bits of the system. As west lakes said, the MCB won't trip unless the circuit is pulling more than 30 amps (or whatever the rating is).
I'm a coward. I have 30mA fast-acting RCDs. Even 30mA can give you a nasty surprise.
If the slugged socket isn't in a kitchen or a bathroom, you don't need a sparks to replace it for you. If you want one to do so, fair enough.