UK Stocks-Factors to watch on April 12

April 12 (Reuters) - Britain's FTSE 100 index is seen opening 18 points lower at 7,239 on Thursday, according to financial bookmakers. * SHIRE: Takeda Pharmaceutical Co Ltd has sounded out creditors for loans, sources with direct knowledge of the matter said, as it moves closer to making a bid for London-listed rare disease specialist Shire that could top $40 billion. * FIRSTGROUP: British bus and rail operator FirstGroup has rejected a takeover approach from U.S. private equit