There is bare­ly a moment, whether it be a fash­ion move­ment or a colour­ful cake, that does­n’t find itself Insta­grammed to death these days. How dif­fer­ent were those post-war decades as British soci­ety dust­ed itself down and embraced a chang­ing world – build­ings, fur­ni­ture, tribes, fash­ion, music, food and hol­i­days, so much was tempt­ing­ly on…