This is a much stronger rumour than the usual run-of-the-mill grapevine rubbish that circulates from time to time. I imagine there's a certain amount of credence to it based on the fact that the Ascension/Falklands contract is only 12 weeks long. I understand that M.O.D. contracts are normally a minimum of 6 months, more normally 12 months so I can only assume that bmi have a need for the aircraft after 12 weeks.
The bigger question is where it will operate from. The powers that be at MAN are absolutely certain it will be ex-MAN, whereas the powers that be at LHR are absolutely certain it will be ex-LHR!
Will make a change to ORD & IAD in any case!!