Burberry has reported a sales surge of almost a fifth thanks to a bounceback in China, but the luxury British fashion brand has warned that London is losing out to rivals such as Paris and Milan, which are enjoying a stronger tourist shopping boom. The British fashion brand, best known for its signature check bags and raincoats, said that global sales grew 18% year on year to £589m in the quarter to 1 July – its fastest growth rate in two years. The company pointed to a strong sales recovery…