How to remove box set, HD etc.?

OK so i recently upgraded to the new entertainment package and added HD and Box sets, the CS advisor on the phone said that I am now able to add/remove box set, HD, etc as and when I wish with 31 days notice. She said I can do it online or via the my sky app.

I've just looked at the app and followed the links afetr the Manage my TV package but all i see is this:

So can I do it or do I have to call them up? I can see the links to add movies though! Do I have to have packs a full 30 days before the option of removing them pops up?

Thanks in advance