BA may seek leave to appeal to the Court of Appeal.
I'm not clear as to what remedies will be available for CC for the period between imposition of changes and the date proper notice of changes to contracts take effect (I would not assume everyone will get a "one-down payment", that may be determined by the courts and may involve more litigation).
BA will have to go through the proper process to change contracts, so it will have to serve 90 days notice of change to contract, possibly with a lot of other changes as well...