I thought for a minute that there had been some major precedential ruling to that effect. The fact that some local judge in some local court somewhere has some view of how BA ought to operate will not likely have any precedential impact on any other rational and sane judge anywhere else in the UK, the EU or for that matter the rest of the world.

OP is certainly free to sue CX asserting that the crewmember illness was not extraordinary in that CX could have stationed relief crew at the European departure station against the possibility that one was taken ill, but CX would do well to litigate the issue as it has little to lose.

Does leave one wondering sometimes as to who runs the asylum.