(Reuters) -About 40,000 British workers for telecoms company BT Group and its networking arm Openreach will hold a national strike over pay in October, the Communication Workers Union (CWU) said on Wednesday. Members of the union, including BT Group’s 999 emergency call handlers, will hold a strike for four days in October: Oct. 6, Oct. 10, Oct. 20 and Oct. 24. The dispute centres on workers opposing the imposition by company of an “incredibly low flat-rate pay rise,” the union said. The company awarded a 1,500 pound-a-year ($1,697.55) rise in April, a 5% increase on average, and has said it w…