UK Stocks-Factors to watch on Feb. 24

Feb 24 (Reuters) - Britain's FTSE 100 index is seen opening down 4 points at 7267 on Friday, according to financial bookmakers. * The UK blue chip index closed 0.4 percent lower at 7271.37 on Thursday, depressed by Barclays stock after the bank reported earnings, by mining sector shares and those trading ex-dividend. * PURPLEBRICKS: Shares in Purplebricks Group Plc rose as much as 19 percent on Thursday after the British online real estate agent said it would enter the U.S. mar