UPDATE 1-UK Stocks-Factors to watch on July 31

(Adds company news items, futures) July 31 (Reuters) - Britain's FTSE 100 index is seen opening up 3 points at 7271.3 on Monday, according to financial spreadbetters, with futures up 0.12 percent ahead of the cash market open. * MITIE: Britain's accounting watchdog said on Monday it was investigating Deloitte LLP's audits of two of the annual financial statements of Mitie Group Plc , the outsourcing company that issued a string of profit warnings la