So sold my sttng and buyer needed to remove backbox to get upstairs, it’s his first pin and I did advise it was a risky venture. He’s getting a load of ground faults and want to be able to point him to the right board? I helped him with the disconnection (Marked the connectors as well)and he took loads of photos and was confident about reconnection although I explained there would no doubt be problems! I’m going to send him a link to this.