LONDON : Vodafone's strategy of focusing on its strongest markets will start to deliver sustainable cash-flow growth this year, even if it takes longer for a turnaround in Germany to show up in the telecom's profits, its chief executive said on Tuesday. Margherita Della Valle has reshaped the British group in the last two years by selling operations in Spain and Italy and agreeing a merger in Britain, where it will become the mobile market leader when the deal completes in the coming weeks. "We