Count
There's actually a lot in your post I agree with, especially your comments with regard to the state of the law in the UK and BA's willingness to use it, but you spoilt it all by stating:
it was clear that sympathetic BALPA reps were prepared to marshall their members to act as strike breakers
No, it was not clear ..... and I suspect you know that.
One, singular, 1, BALPA Rep resigned his post to become a Volunteer Cabin Crew Member. Our Comms from the remaining Reps and the Company Council were adamant and consistent in stating that BALPA should remain neutral over the dispute (and with your apparent grasp of UK industrial legislation you will of course understand why BALPA had to be neutral in it's statements and more importantly it's actions.....) There was no attempt by either BALPA as an organisation or it's Reps, to marshall anyone as strike breakers.