(Reuters) – Fortress Investment Group is plotting a 5 billion pound ($6.8 billion) takeover of Britain’s petrol stations giant Motor Fuel Group (MFG), Sky News reported on Saturday. The U.S.-based private equity firm is lining up advisers to work on a bid for MFG, the report said, citing unidentified sources close to the process. SoftBank-owned Fortress and MFG did not immediately respond to requests for a comment. Last year, MFG’s owner Clayton Dubilier & Rice (CD&R), a U.S. private equity group, had beat Fortress to buy supermarket group Morrisons in an auction. The 7 billion pound takeover …