UK Stocks-Factors to watch on Aug 18

Aug 18 (Reuters) - Britain's FTSE 100 index is seen opening up 42 points on Thursday, according to financial bookmakers. * The UK blue chip index closed 34.77 points lower on Wednesday at 6859.15, as a slump in Admiral shares dragged Britain's top stock index down further from 14-month highs, after the car insurer said that market volatility caused by Brexit had hit its solvency ratio. * SAGE GROUP: City of London police arrested a Sage Group employee on Wednesday at Heathrow A