So no this is not an area for BALPA to negotiate because it does not apply to flight crew.
This ruling only applies to those who are contractually obliged to work overtime.
I'm no doubt mistaken but that sounds very much like "BA's" Forced Draft to me ....it was in the contract (Bidline) and unless you could get out of it due to exceptional circumstances you sure as heck were required to work it.
That said the papers seem to be saying this is going to appeal, will take years to resolve, and in any event I doubt BALPA has the stomach for another tribunal, so I suspect it's all "moot" anyway.