My plot neighbour was going away for a fortnight just as this heatwave started. He covered some of his more vulnerable plants with fine fleece stretched over some canes. I watered for him 2 or 3 times but noted that the fleece did help to protect them from the worst effects of the sun and heat, I imagine in the same way it helps to protect from the ravages of frost in winter. I’ve made a mental note to try this out when I go on holiday.