I would ask how the courts would view a large corporate company deciding more then 4 years after the illegal secondary strike to take the union involved to court just after said union had authorised legal industrial action ?
Now it wouldn't look at all like revenge now would it ?
Unfortunately Law is not about what is fair, or percieved as "revenge". It is purely about the facts and how they relate to the Law of the land.
It would be wise for all to take note of this. You may think BASSA going on strike would be legal because BA is being unfair. The judge will have no interest in "fairness", they will be concerned in seeing that both parties acted legally that will be the only basis for a decision.