FREDA
At this point I see little advantage in moving the Vikings to the civil register simply because of all the spending that has been made to keep them on the military register.
If the decision had been made to change at the start of the pause some savings could have been made and the aircraft retuned to service a little more quickly, as the recovery ramps up from a paperwork setting up exercise to an aircraft fixing one industry capacity will become the limiting factor to the speed of recovery.
The technical reasons for this have been well documented above, from the flying side BGA qualifications are not good enough as these are intended for private flying, the VGS is in civil terms an operation requiring an AOC and just like any commercial operation it requires its pilots to hold commercial pilot qualifications. ( please don't see this as a criticism of the flying abilitys of BGA instructors it is a paperwork issue )