Value retailer, Peacocks, is on track to open around 40 stores this year, it has been revealed.   The comopany, whose aim is to become the most successful value-for-money clothing retailers in the country, opened 13 stores in the first half of last year.   Now Peacocks, which opened its 300th store in the UK in Halifax at the end of October, is on target to open between 35 and 40 stores this year.