It’s time. When the sun shines on England’s green and pleasant land, a kind of delirium grips the country, from lobster-red beach bods to blackened BBQ chicken legs, fuelled by cans of lager and the cheaper end of the white wine spectrum. Swap the lager or the wine for that oft-neglected cocktail however – the summer cup or the fruit cup – and the English summer is transformed. Out of madness comes sophistication: Wimbledon, strawberries and cream, picnics in the…