One thing that doesn't seem to have registered with the union is that BA's continued training of staff to act as cabin crew is building a pool of employees capable of standing in in any crisis in the future. To all intents and purposes, BA are mitigating against the possibility of future strikes, even if the union back down on this.
Refresher courses would be required no doubt, but it's an interesting strategy, and one that should concern them now the precedent has been set.