UK Stocks-Factors to watch on Nov 7

Britain's FTSE 100 index is seen opening 33 points higher at 7,074 on Wednesday, according to financial bookmakers. * BHP: Mining giant BHP Billiton expects some interruption to its Australian iron ore exports after a nearly 3-km-long train loaded with the commodity was forcibly derailed this week after running away en route to a key shipping hub. * THOMAS COOK: British holiday company Thomas Cook Group Plc said it plans an independent hygiene assessment at an