UK Stocks-Factors to watch on June 21

June 21 (Reuters) - Britain's FTSE 100 index is seen opening 49 points higher at 7,676 on Thursday, according to financial bookmakers. * BP: Australia's largest supermarket operator Woolworths Group Ltd cancelled a A$1.8 billion ($1.3 billion) sale of its petrol stations to BP Plc on Thursday, after it was blocked by Australia's antitrust regulator. * BOE: The Bank of England may lay some groundwork on Thursday for an August interest rate rise, if it judges the economy is