"And in rural England, even in 2018 a whole 24 hours uninterrupted power (no sags/surges/glitches) can be a luxury!"
Wow! That surprised me! I had no idea.
Sometimes our mains power is a bit dodgy in the winter from ice storms or traffic accidents knocking out poles, but a year or two can go by without incident I think. I can't think of the last one. So maybe 3 years. I think 90+ % of our power is derived from hydro. https://en.wikipedia.org/wiki/BC_Hydro
OK, it's 95%.