Bank nurses tend to be existing nurses working extra hours and doing bank shifts. As for student nurses, if they were working at the nightingales, they then weren't doing their various rotations at existing hospitals leaving a shortfall there! Can't comment on military medics as I have no idea how many there are but same thing would apply, ie if they are working at the nightingales then they aren't doing their usual roles.the Nightingales were planned to be staffed by mix of army, bank nurses and student nurses (sister was offered option to go there in lieu of training). they weren't used be they cleared out the hospitals and lockdown worked, so they weren't needed.
degrees are a curious issue, came in during mid 90's. were they necessary because of role change, or did the role change because they all had degrees? i gather more the latter.
As for the degree, I wouldn't read too much into it other than it gave them a professional status that wasn't recognized as much when they were State Registered Nurses or State Enrolled Nurses. I don't know for certain but I'm assuming that most of the course is the same as was being taught before except now of course they will be doing a dissertation.