UK STOCKS-Factors to watch on March 17

March 17 (Reuters) - Britain's FTSE 100 index is seen opening up 1 point at 7,416 on Friday, according to financial bookmakers. * BP: BP Plc on Friday said it had sold around half its roughly 20-percent stake in New Zealand Refining Company Limited for NZ$80.4 million ($56.2 million) as part of a global portfolio review. * BHP BILLITON: The striking union at BHP Billiton's Escondida mine in Chile, the world's biggest copper mine, sai