Australian here, waving from Melbourne. I'm so sorry, MNers and general Brits. My fingers are crossed that the worst is over and there are no more losses.
Meanwhile, maybe do as we do in heatwaves:
No barbecues
No unattended flames of any kind, especially candles; Victorian terrace rows can go up like that because of attic fires, and these happen in Melbourne and Sydney too
Stub out your cigarettes really well, don't just chuck 'em
Pour your rinse water (dishes, shower) on the garden, if you have one
Cool, moist washcloth on the back of your neck
Slip, Slop, Slap -- slip on a T-shirt, slop on sunscreen, slap on a broad-brimmed hat. A cotton-drill cricket hat is good. (If you do 1 and 3 you don't really need the sunscreen on your face, I reckon.)
Please do consider doing a First Aid qual, which a lot of Australians have in case we need to help as volunteers in emergencies.
If your local fire brigade does volunteer training, and you're able to do it, consider this too. The climate is changing, and we will need all hands on deck, wherever in the world we are. 🌞