By James Davey LONDON (Reuters) -When Amazon opened its first grocery store outside the United States in 2021, its choice of a site in west London for a cashier-free store was seen as the start of a major assault on Britain’s $290 billion food market. That store closed in 2023 and this week the group said it planned to shut its remaining 19 Amazon Fresh stores - a failure that highlights the brutal economics of UK food retail, and how one of the most powerful retailers in the world may still be feeling i ...