AH64...
The Ts and Cs are strange in BA, because in the majority, they are decided by the "agreement" i.e. between BA and BALPA.
The effect is that BA could quote you a starting salary of £40K, and 2 weeks after you joined, you salary is cut to £20K. All legit, if in accordance with BALPA. Naturally, only a theoretical situation...
Not quite sure where this sits in law, but presumably OK...
NoD