I went to close my account in the app. It’s only set up to send an email directly from the Apple Mail app (which I don’t have) and there’s no actual email address given. If closing an app–only account by email only wasn’t ridiculous enough (why not just authorise in the app?) then defaulting to one particular email app is just bad UX.
There’s nothing in the account, so I guess they’ll get round to closing the account in a couple of months when they realise they can’t take any fees from me.