butterandjam
South east UK is already short of water, and as that gets worse , it will be prioritised for hygeine, medical care, farm crops and livestock, and industry.
Rivers will probably be unfit to swim in. Forget swimming pools, spas, and a bath at home. Showers will be rationed ( like bathwater used to be); a short shower twice a week. Damp wash with a facecloth if you're lucky.
As irrigation reduces or fails, UK food production of basic harvests ( grain, potatoes) is going to be a big problem. We'll be increasingly dependent on imports.
You southerners had better keep your big suntrap windows because you'll need them to trap heat in summer when CH is too expensive. AC takes a lot of fuel, so don't count on that. Better install some shutters or exterior awnings for summer. Install an opening roof window so you can vent hot air via the loft in summer. Plant some shady trees.
We have the shady trees, planted nearly 100 years ago - thanks whoever did that. Means we can grow cottage garden plants in the shade.
I think an opening window in the loft is a brilliant idea - cool house here, but the loft gets boiling & if it's hot for a while, heats everything else up.