Buying the airframe is the easy part ...
It will probably take up to three years to train sufficiently capable crews to operate whichever jet we get.
There has been ample time since the capability was 'gapped' for enough studies into which jet it should be to be completed.
The decision process does not start on the date that the SDSR report is made public, enough time has already been lost.
Just get on with it ...!
It's a plain as the nose on your face what's going to happen ...