After a few prods from the universe that the electricity system is man-made and thus prone to failure :), I’ve taken the steps to buy and install a backup supply and surge limiter thingy from https://www.EBuyer.com
It’s called an “APC Back-UPS RS 800VA USB/SER 6 Outlets With AVR & Surge Protection” and seems to work fine for 2 PCs and all the add-ons for over five minutes, which is good enough to give me time to save stuff etc.
It’s gone up in price since I got it. It cost me £89.85 in the middle of January and included everything. It’s back over £90 now, which is still cheaper than most vendors.