We have an info page drafted up that we’re going to put live later this week. But you can check out TrueLayer’s Privacy policy here: https://truelayer.com/privacy
They are regulated by the FCA, much like banks and other open banking services - so would suffer large penalties if they used details for anything other than what they’re given permission for.
Long term we’ll move to using Open Banking APIs, but they’re not yet provided by for Credit Cards (they’re due from the main banks by September)