I'm also in the UK and too hot!
It's annoying, because when it's sunny, I feel happy and warm (I often feel too cold) and want to sit in the sunshine, but when I do I overheat without realising and start to feel ill. And I get sunburn. And the very dry skin on my hands feels worse. I'm usually okay indoors, or walking outside for short periods of time.
Last night was just too hot, though. It didn't have the nice sunny feel, just too hot.
Next door's cat often comes into our house so we see her a lot and she seems fine in this heat, despite being a black cat (shorthair though).
Good idea to put a cushion in the freezer. I will remember that, it might be useful.
We better not have another heatwave. I don't do well in temperatures above 25C