Ah, yes, this would be the same UNITE that pulled the rug from under the last "strike that never was". Face it, you are on your own. There is NO chance of secondary action, and yes, there are PLENTY of crew at LGW. You need one cc per pair of doors or 50 pax, so a 777 can go with 8 (vs 12 at LHR) and a 747 with 12.
BA HAVE to win this. Future investment in the company is conditional on work practice agreements being made more efficient (in the case of LHR cc, MUCH more efficient.) Without future investment the company will go under, so with that much at stake WW has to win or he might as well go home.
In that case, it would be a very pyrrhic "victory", but at least the cc would be able to congratulate themselves in the dole queue that they kept their box payments to the end!