UK Stocks-Factors to watch on May 5

May 5 (Reuters) - Britain's FTSE 100 index is seen opening up by 25 points, or 0.4 percent, on Thursday, according to financial bookmakers. For more on the factors affecting European stocks, please click on * The UK blue chip index closed down 73.57 points, or 1.2 percent, at 6,112.02 points on Wednesday, as basic resources stocks extended the previous day's losses and retailers came under pressure. * SABMILLER: Australia's antitrust regulator on Thursday cleared beer giant Anheus