By Amber Murray Sainsbury’s told markets this morning that profit after tax in the first half of the year fell by 51 per cent to £76m due to post-tax costs of £176m predominantly related to the restructuring of the financial services division. However, the company’s grocery sales rose by five per cent, ahead of the market, and retail sales rose by 3.4 per cent. Growth in the retail arm offset a five per cent decline in sales at Argos, the company said. Overall, the firm reported a total underlying profit before tax of £356m, up 4.7 per cent. Sainsbury’s bank sale hits profit In January, Sainsb…