Not in the UK but in Germany, experiencing the same heat wave: it’s brutal. We had temperatures exceeding 40°C in some places and pushing 40°C basically everywhere else. In my top floor, non-AC’d apartment, we measured 34°C on multiple days and couldn’t cool down below 30°C until well past midnight.

For the lazy yank: 40°C = 104°F, 34°C = 93°F, 30°C = 86°F.