Legal Challenge?
Cos 08 contains the following:
9.1. An Annual Discretionary Bonus equivalent to one (1) month’s Salary will normally be paid to all Officers with twelve (12) months’ qualifying service as at 31st December in the relevant year.
Further on "normally" is defined. The definition of all officers is simple and I can't see that this definition can be altered by further defining a Captain as Level D; that attribution of a Level is in anycase purely administrative.
I am not a lawyer but I would read the Cos to mean that the bonus should be paid either to all Officers or to none at all. I suggest that the AoA get the lawyers onto this straight away if they have not already done so.