This has been mooted for a while as a justification for keeping the Tranche 1 jets to maintain "combat mass". It would be an ideal opportunity for some of the squadron to be a cadre of FTRS, retaining a diversity of experience and, perhaps, becoming something of a "rest tour". Like the US Aggressors there would certainly be kudos and esprit de corps on such a unit.
Perhaps consideration could be given to a multi-type unit with a flight of Typhoons, a flight of Hawks/Scorpions and a flight of T6/Tucano? This would be ideal to provide full spectrum threat training across the RAF - it's not just FJs that need "red air" for training and not just "near peer" opponents we may find ourselves going air-air with.