UK Stocks-Factors to watch on March 31

March 31 (Reuters) - Britain's FTSE 100 index is seen opening down 19 points at 7,351 points on Friday, according to financial bookmakers. * SMITHS GROUP: The U.S. Justice Department said on Thursday it will require Smiths Group Plc to divest Morpho Detection LLC and Morpho Detection International LLC's global explosive trace detection business for Smiths to proceed with its proposed $710 million acquisition of Morpho from Safran SA . * JOHN LEWIS: John Lewis ,