By Amber Murray High street retailer River Island has slipped into the red with a £30m loss before tax as it struggles to hold up against online competition and rising costs. The company reported a loss before tax of £32.3m in 2023, down from profit of £7.5m in 2022, according to newly-filed accounts with Companies House. Turnover fell 15.1 per cent to £701.5m, from £825.8m in 2022, while earnings before interest, tax, depreciation and amortization (EBITDA) fell by 146 per cent, from profit of £26.5m in 2022 to a £12.5m loss in 2023. The retailer blamed its struggles on a combination of higher…