UK Stocks-Factors to watch on April 28

April 28 (Reuters) - Britain's FTSE 100 index is seen opening up 1 point at 7,238 on Friday, according to financial bookmakers. * BARCLAYS: British bank Barclays Plc faces shareholder revolt over whistleblower inquiry after a corporate governance firm advised shareholders not to back his re-election to the board, The Times reported on Friday. (http://bit.ly/2qdvJ63) * BP: BP Plc was restoring production on Thursday afternoon at two crude distillation units at its 4