yo bro. Not sure we have talk on this when we exchange the frags. How old is yr flat? My case is bit similar as yrs but I didn't check my neighbors if they have trip as well. So when at work, I heard a loud thunder, my balls shrink.
Touch wood but after I change my elcb, so far so gd. Just take a pic of yr elcb n go sim lim tower, level 3, left or right shop of the going down escalator. Much cheaper than getting the service of an electrician.