Phew! I am exhausted! Today I cleaned everyone's cages and moved them around a bit, re-did their toys and then three of them got an upgrade in size! Took 6 hours!
My ringneck was in the biggest cage alone. In the next size down was the 'tiel alone. Then the next size down had the princess alone and the smallest had my lovebird.
After everyone's cage has been cleaned to within an inch of its life, the princess and the cockatiel are now in the biggest cage, the ringneck is in the middle size and the lovebird got an upgrade.
No fighting yet. Fingers crosses!

to come (still looking for that damned camera charger!)