On Thursday, the listed sportswear retailer JD Sports Fashion lowered its full-year profit forecast, prompting a billion-pound slide in the company’s market valuation. It had earlier expected profit to be in line with market expectations of £1.04 billion (€900 million), but it stated this week that the figure would now be between £915 million and £935 million for the year ending February 3. The retailer cited higher costs and a slowdown in consumer spending. The mild weather conditions also impacted the forecast, with the company saying it had experienced subdued demand for apparel. Jonathan Pritchard, a retail analyst at Peel…