The situation is actually quite simple, and we know everything even if the court tries to keep things secret.
The Home Office wants access to “secret” data of terrists without telling them. I’m afraid they might want access to my “secret” data next year because I talk about Fararse, or about a rapist, racist, grifter and convicted felon who is the son of a racist slum landlord.
We know that Apple has no ability to give them the secret data of terrists _without also having access to every citizens data_. And with their secure iCloud storage they have no ability to deliver that data without lying to all their honest customers. So Apple turned that feature off in the UK.
So whatever they try to hide in court, we already know it. Apple is not legally allowed to tell you, but they don’t have to. And would they be allowed to tell you “if we were ordered to hand over your data we wouldn’t be allowed to tell you”? Surely yes. And even the least intelligent customer would ask themselves “why would they say that”?