MC,
There is a difference between what they say and what is legally the case.
AFAIK BASSA claims that BA have imposed unilateral changes that are contractual. BA does not dispute the imposition, only that they are contractual.
The last couple of weeks a lot of discussion has taken place over subjects that were (legally) not part of the problem. BASSA has proposed different changes based on the assumption that the changes were contractual. BA refused to discuss this (logically) since they say the changes are not contractual and therefore there is no need to discuss them (or for BASSA to offer alternatives).
So, although BASSA makes us believe they are protesting the changes, they are in fact saying that BA is in breach of contract. A strike is not the way to settle such an issue, a legal case is. That is what is being decided Feb 1st.
BASSA can no more strike about non contractual changes than they can strike over what aircraft BA decides to buy. The real issue is therefore if the changes are contractual or not. If they are not, than BASSA has no legal grounds for a strike. It really is end of story then. Ballot or no ballot.
I do not know how to explain it more clearly.