Not being a labour lawyer, my assumption is that given only about 5200 of 12000 known CC are accounted for in the Unite vote, the remainder, or at least a majority of the remainder will have accepted the offer made to them as self-declared non-unionised employees by BA.
If this is the case, then surely they are contracted under the new terms and conditions and unlikely to support any strike action. Or... in this shifting sandbox, am I missing something?