Ahh banding.
Some points from my view.
Should people be paid differently depending on unit? Yes
Have "management working together with Prospect have erroded the pay at the smaller units"? I think all units have had pay rises in the last 5 years, so I would dispute that comment by throw a dyce. Was it done to keep the larger units "quiet"? I don't personally think it was but that is my opinion much as throw a dyce has his.
The argument of "I can't get released from my Band X unit, so cannot come to a Band 5 unit" is a sound one, NATS has a poor record in recent times of releasing staff. However people can move units, and have recently moved to my Band 5 unit. But to say that I am unable to be posted to a Band 5 unit, should that result in Band 5 money on the basis you cannot be posted there but want to? That is the argument some try to make I feel.
Remember we as members of the union asked for some form of banded structure. We as members were presented with it at conference a few years back and accepted it. We are members voted for it, I am told by union reps that more than just the big bad Band 5 units voted in favour for it so some non-Band 5 to be units must also have had members voting yes.