That's an incredible story! It's amazing what you can discover when you start back-tracing issues like this.

A few months ago, my house started having intermittent failures.

It turns out that some road works caused one of the phases in my house to leak into the other phase, which caused a whole array of problems, but only in specific areas of the house.

We discovered this by piping 40kV into the wiring and listening to crackling in the ground, where we found the faulty cabling.