UK Stocks-Factors to watch on June 13

June 13 (Reuters) - Britain's FTSE 100 index is seen opening up 1 point at 7,705 on Wednesday, according to financial bookmakers. * SAINSBURY: A British parliamentary committee will question the CEOs of the UK's no. 2 supermarket Sainsbury's and its third-biggest supermarket Asda ahead of their proposed combination, as scrutiny of the deal cranks up. * DELIVEROO: Deliveroo will allow restaurants to use their own riders for orders placed through its takeaway food app, in a