By William Schomberg LONDON (Reuters) -British consumers cut back on shopping in May in the face of fast-rising inflation, and a measure of their confidence sank to a record low this month, according to data that underscored the scale of the cost-of-living squeeze. The Office for National Statistics said on Friday that sales volumes in May fell by 0.5% on the month, a slightly smaller decline than the 0.7% drop expected by economists polled by Reuters. But the ONS also slashed its estimate for month-on-month sales volumes growth in April to 0.4% from an originally reported 1.4% after an annual…