There was a comment from someone yesterday that said BA's orignal offer included no New Fleet, as well as one down and changes to the disruption agreements, and shares like the pilots. Is that correct? No one came on to call him/her on it. If so, New Fleet need not have been an issue.
My own thoughts, before I saw that, was that they, BASSA, should have bargained around one down in order to get cast iron agreements on pay/promotions/allowances/flights transferred to new fleet for legacy crew when New Fleet came in. That's what bargaining is about - give on one thing, get something else in return. One down can't be that bad if they do it at LGW.
As to voting for a strike, if you give your loyalty to the union, you deserve to have that loyalty repaid by constructive negotiating, if they don't do that, you can take back your yes vote.