I feel for you, as most UK homes aren't designed to deal with that kind of ambient heat.

• If it's safe to do so, open a couple of windows to allow air to circulate around the home - it might not actually be cooler, but the air currents will make it feel more tolerable.
• Fill the fridge with bottles of tap water & if you have an icebox, make ice cubes. The chilled water can be a real pick-me-up & the ice cubes can be placed in drinks, or in a bowl in front of a fan to make a rudimentary air conditioner.
• If you have a metal/enamel bath, go lie in it - it will conduct some of your body heat away.
• If it's not already humid, fill the bath with water from the cold supply - you can either get in, or just allow that body of water to wick some of the temperature from the air.
• If all else fails, find a library/public place with air/conditioning & hang out there during the hottest part of the day.