It would certainly take very deep pockets to even attempt to prove otherwise, with absolutely no guarantee that the outcome would be in your favour.
I am not advocating it goes down the legal route but I do not think it would take very deep pockets to make the legal challenge. It will only take one person, BALPA member or not to have a punt at it. Most people have legal protection on their house insurance. I would bet a fiver that it would be good enough to get the legal ball rolling.