A Next store in London (PA) (PA Archive)Next's efforts to limit the impact of the Iran war and avoid raising prices in the UK will come under scrutiny after the retailer warned it was facing rising costs. Investors in Next, which is often thought of as a bellwether of the high street, will be hoping to see sustained momentum on sales growth over recent months. In May's update, Next said UK sales rose by 4.4% over the previous three months, but said sales growth was set to slow to 1% in the second quarter as it comes up against tough comparisons from a year earlier. Next also warned in May that it was facing an estimated cost hit of £47 million from the Iran war, up from the £15 million guidance given in March. "Closer to home, the inflationary impact of higher energy prices threatens to heighten input costs as well as crimp consumer demand.