We always have grand plans to spend our days in the great outdoors when we take over an Airbnb in the countryside or by the sea – but sometimes the British weather has other ideas. What you need, then, is a hot tub – a steaming refuge that you can slip into whatever the elements are doing. We’ve handpicked a clutch of the smartest Airbnbs that also come with a private hot tub, for summer sundowners or chilly evenings.