By Laura McGuire Primark owner Associated British Food (ABF) has raised its dividend following a strong set of results, thanks in part to a Rita Ora-driven campaign. The retail and food giant’s board revealed operating profit grew 39 per cent over the period to £911m, helped by a “return to normality” in markets such as sugar and its grocery arm which makes brands such as Blue Dragon, Ryvita, Jordans, Kingsmill and Twinings. Sales at Primark rose 7.5 per cent, slightly below the 7.9 per cent increase the company reported in the 16 weeks to January. ABF blamed a slow start for many cold weather…