Yeah, my fuseboard is a weird one too -- there's technically two: one from the 80s and one from the 00s, and the master kill switch after the meter or before the meter simply doesn't exist. No RCD breakers for killing sudden surges.

If there was a master switch, I'd feel less nervous - follow a youtube video on how to junction a circuit, switch it on / switch it off to test. Without... hmm, I might just get an electrician