Regarding BALPA/T&G just look at what happened to Sabena pilots, many moons ago, when "general unions" took on pilots and negociated for them. They landed with so little as they were the margin the negociators would play on. They got crushed.
Never, NEVER go by non-pilot unions ! This is what's happening in France as well. The French got it all across when the governement wanted to have pilots represented by ground people. They understood their fate would be guided by people who have no interest in them. A strike threat for this coming summer has put all back in place and they'll have their own unions.